Heat Pumps & Mini-Splits

Parent Q&A

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  • We are at the point in our home renovation where we need to cut out some of the scope. We have found some significant plumbing issues that we have to address, so we need to find the money somewhere. We were planning on replacing the defunct HVAC system with a ductless mini split system. But it is just too expensive at this point. We are insulating the walls and attic and replacing the windows and exterior doors. Our contractor recommended just putting in a few recessed electric heaters until we are ready to install the mini split system. Has anyone done this before, and can you share your experience? Are your PG&E bills astronomical in the winter? Is there another potential solution you would suggest? We could also do a gas wall furnace but running the gas lines and using a gas appliance seem like not the best direction from a sustainability point of view - but maybe I'm missing something. For weather context, the house is in west Berkeley.

    It is difficult to advise without knowing what your defunct hvac system is. But you may want to patch that up and keep it running. 

    alternatively, you may want to consider using one or two ptac units. They are heat pumps adequate for about one room. They are easy to install because in addition to using no ducts, they use no pipes. They are a bit noisy, though. 

    I've been in the same quandry. We insulated earlier this year and it made a big difference. I'm looking at electric under floor heat mats for bath and kitchen. There are also toekick heaters   —they get raves from some and total fails from others—basically mini wall heaters but could be a good stop gap for you.

  • Heat pump install quote 20k - reasonable?

    (11 replies)

    Hi, we’re looking into replacing our aging furnace with a heat pump for heating and cooling. No current AC. Received a quote for a 3 ton Mitsubishi for 20k including all permits and replacing all ducts. 1200 sq ft house in Oakland. Anyone done something similar? Is this a reasonable offer? Anyone have HVAC company recs? Thanks!

    We installed a heat pump for hearing and cooling last year. We did not replace ducts and it was still a little over $13k. I do recommend getting a quote from more than one place. The plumbing company we used was a but cheaper than another company. 

    Well, I don't know if it's reasonable, but it seems to be the going rate! We paid a tick more for our 1,400 sq ft home and went with Hassler so think the quote you got is within bounds. They were professional and got the job done.

    We had a Fujitsu heat pump installed last year for the same cost ($20K), which included replacing ducts and some asbestos tape abatement. The cost of the machine itself was around $14K. We also have a similar size house. We had gotten three quotes that were all very similar and ended up choosing this company (A-1 Guaranteed) because of the good reviews. It was expensive but we are very happy with the heat pump and having AC has been a nice bonus! 

    Here’s a point of comparison: our house is a tad larger and on two levels.  The estimate we received was more than double 20K.

    In Marin County, two months ago, an estimate from the big local HVAC company for a Mitsubishi system covering 1350 square foot home: $38,000.

    I did not proceed as the cost seemed high. I have had verbal ball park estimates as low as 15 k. But not Mitsubishi.

    20 k sounds great, as it is probably almost identical to the system design proposed 38K. (The design was bare bones.)

    We had a certified installer for a Mitsubishi for a slightly larger house (1700 sqft) with new ducts last year and the cost was similar.  Feel free to DM for more info. 

    I just had a 2.5 ton Mitsubishi system installed and mounted in the attic of my 1600 square-foot home. I had only a single gas gravity floor heater, no ductwork, no ac. Our project included removing the existing attic insulation, sealing the extensive air leaks in the attic and floors, insulating 200 square feet of the coldest exterior bedroom walls, removing the attic knob & tube wiring and rewiring everything, re-insulating the attic, cutting in 10 ceiling registers in plaster, cutting a bigger attic access hole for the air handler (fan), installing an all-house filter, installing all the ductwork, installing an outdoor condenser, unit installing new wall-mounted thermostat. Removing existing gas floor heater. The contractor is applying for multiple rebates but we’ve learned that some of the programs are out of funding. Im thrilled with how everything came out. 

    For just the heat pump (air handler, ducting and condenser installation, removing existing gas gravity heater) I got three quotes that ranged from $22k to $32k. I went with the $24k quote and added the other items. 
    I also looked at leaving the existing single gas gravity heater and adding a 3-mini split system to heat/cool the three small bedrooms (80-120 sf) in the rear of my house. They were actually the only rooms that were too hot and too cold. The quotes were the same as for conditioning the whole house so I went big. This way I reduce my natural gas use, too. I had a $300 gas bill last March and am ready to move on. (Still have gas dryer and hot water heater.) 
    I do recommend that you consider a whole house air filter in-line with your system. It may require resizing your return plenum but I think worth it. Please feel free to reach out if you have any questions.

    Good Luck!

    If you're Excel-savvy, you can check comps for your project by downloading the data from TECH Clean California (a statewide heat pump incentive program that I work on, thus how I know about this): https://techcleanca.com/public-data/download-data/  If you download the "TECH Working Data Set Single Family" (right column of website) you will get an Excel file with data on thousands of heat pump systems installed across the state over the last 2 years.  You can filter the results down to HVAC systems with duct replacement and look at the range of project prices across homes similar to yours.  Hope that helps and you love your new heat pump!     

    3 tons sounds excessive for 1200 SF! see: https://www.pickhvac.com/heat-pump/sizing/.  I'd recommend getting multiple quotes, and seeing if someone can size down, which should also help with up-front costs and ongoing electricity bills. 

    We are a 1300 sq ft flat on the bottom floor of a duplex in Berkeley and had the furnace and all of our ducts replaced with a heat pump, plus air sealing and floor insulation for $30k or so, so that bid doesn't seem bad at all. Don't know how your specs are different from the Fujitsu heat pump we had installed, but probably still worth getting a second bid just to feel confident about moving forward with whoever you want to work with.

    Eco Performance Builders did our project and we highly recommend them! Thorough scoping of the project with explanations of why to do or not do elements of it, and everyone who worked in our house was fantastic, especially considering both my wife and I work from home.

    We're very happy with the results - much smoother moderation of temp when heating than furnace and the A/C has been lovely on really hot days (which are only going to get more common from here unfortunately).

    Whoever you end up using, be sure to check if any of the work (suchas the new ducts, and possible adding insulation) qualifies for rebates from BayREN.  If you are in Albany, they are also offering rebates to residents  for heap pumps; not sure if other cities in the area are doing that.

  • Ductless mini-split options - help!

    (2 replies)

    I have decided on a ductless heat pump mini-split system for my house and I’m thrilled. 
    I’m keeping, for now, the very old gas gravity floor heater which heats the front part of my house. 
    What I’m adding is a Mitsubishi 3-zone system to heat/cool the three other rooms in my split-level house. (Bedrooms, office). 

    The two downstairs rooms will get square registers (cassettes) in the center of the ceilings. The upstairs split-level bedroom will get a wall mounted unit. Each zone heat pump will be 9k BTUs. 
    I’ve gotten quotes for a 24 and 30 BTU outdoor condenser system. 
    Any pros and cons to the condenser size? Prices, footprint, and sound aren’t that different. I don’t want to oversize and waste energy. 
    About the controllers: most folks get “remotes” which generally I don’t care for. I dont want to be dependent on an app for temp control, either. I’d like a hard-wired, walk-mounted, programmable thermostat with override and on/off capability like I have for my gas heater. Has anyone used this kind of control? 
    Also, they offer special filters which sounds great as I want indoor protection during future smoke events. 
    Any feedback and personal experiences would be so appreciated!

    I don’t have any answers to your questions, but want to caution you to consider your utility bill impact of combining gas and electric heat- you may want to try to talk to someone at PG&E before finalizing any decisions. California energy policy mandates tiered usage rates where the more energy you use, the more higher the electric rate. It’s meant to incentivize energy efficiency/conservation. But of course switching from gas to electric heat will increase your electric usage but be an overall climate win, so when you switch to electric heat, you can tell PG&E and they’ll raise the “baseline” of how much energy you can use in the cheapest tier. I don’t know how it works if you still have some gas heat in your home, though. You may not be eligible for the higher baseline and may end up paying much heftier electric bills, so it’s worth looking into.

    You are smart to keep the gravity furnace, and to augment it for additional needs. It requires no electricity at all, not even for the thermostat, so you'll enjoy a heated home even when the power is out. And it's completely silent. We had one in our previous house -- it was 80 years old, completely maintenance free, and bullet proof. So many have been ripped out by people who didn't understand what they had. I wish our new home had one.

  • Anyone have a two-stage heat pump?

    (1 reply)

    Would you be willing to let us come check it out? We are electrifying our house and will be installing a heat pump, but our contractor is encouraging us to get a variable speed heat pump (which is more $$ and seems like it might be overkill for Berkeley climate). Would be great to hear about a two-stage pump in action first. I hear they are louder but don’t know how loud that is. 

    If you're interested in seeing a variable speed ductless minisplit heat pump system (Mitsubishi), let me know. We had it installed in August 2021 by Electrify My Home (highly recommended). Variable speed is definitely not "overkill" in our climate - it's more about operational efficiency. Single stage and two-stage "old school" systems have a much larger footprint and are much louder. What is overkill is having a backup furnace - which one of the contractors we got a bid from recommended! I actually think variable speed makes the most sense for our climate because our climate is so mild. We don't deal with extreme temperatures so the variable speed can turn on just a little bit to warm or cool the house. Single phase go from 0-100% when they turn on, and two-stage are only a little more efficient. Here's a good article explaining it https://www.mitsubishicomfort.com/blog/make-the-best-of-your-heating-and...

  • Hello, does anyone know if there are regulations that govern Berkeley residents for where on our property we can install a condenser for a heat pump, i.e., not within 3 feet of the property line, not in the front yard, etc.?  I've been searching the regulations with no luck.

    The regulations won’t be written explicitly - you have to figure it out based on the zoning of your lot and the adjacent lots.

    You will have to meet the noise standards at the property line based on the zoning of the area you are in. Those can be found in Berkeley Municipal Code 13.40 Community Noise. The section on Exterior Noise covers the sound level limits. The unit cannot be audible above the listed limits at the property line no matter where it is placed.

    If you intend to put it in a required setback, you will also have to meet the Zoning requirements for what is allowed in that setback based on the zoning for your parcel. Berkeley Municipal Code 23.304.030 covers setbacks and Table 23.304-2 shows the maximum projection of heating and cooling equipment into the required setbacks.

    If in doubt, you can stop by the zoning counter and confirm what you want to do is ok with Planning. Just keep in mind, even if the location is allowed by zoning, if you violate the noise ordinance and get a complaint, you could still have to move it.

    It might depend on the details. In Albany (where we're about to have a very quiet heat pump installed), there's a strict 5-foot setback, regardless of decibel level (and they vary - a lot!).  I've heard from our contractor that in some jurisdictions (Piedmont?), the required setback depends on the operating decibel rating (which makes much more sense).  No idea how it works in Berkeley.  One Berkeley resident I know has their condenser in their front yard, so I assume that's allowed (at least in their zoning area - that may also vary). I'd think that any contractor that regularly installs heat pumps in Berkeley would be familiar with the regulations, but you could also just call and talk to someone yourself.

    A qualified plumber should be able to come by for a free estimate and also identify ideal locations for the unit. We recently installed one, and we told the plumber about 2 potential sites that we had in mind. The plumber said both would be in violation of the set-back requirement. He walked around the property and identified a place that would be ideal and compliant.

    Following up on the first comment - as it states it varies by property. First look up your lot's zoning here https://berkeleyca.gov/construction-development/land-use-development/zon...

    Then find your side yard setback and rear yard setback based on that zoning:  https://berkeleyca.gov/sites/default/files/2022-02/Zoning-Information-Gu... 

    Generally you're not supposed to build anything in those setbacks. But that Municipal code section 23D.04.030 says that for mech equipment, you can project into your sideyard setback by 1.5 feet (or 2.5 feet for any sideyard on a corner lot that is adjacent to a street), 2.5 feet into your rear setback or front setback.  Caveat on the sideyard: you must maintain 3 feet between equip and lot line. 

    One thing to note. The city of Berkeley knows that heat pumps are quieter than traditional outdoor mechanical equipment.  They are committed to electrification and are looking at what they need to change in their regulations to encourage it. One action item they are planning is to "allow setback exemptions for heat pump condensing units and conduct a study of heat pump noise levels to exempt any models that fall under noise thresholds to streamline installation.revising their zoning to allow heat pumps to be closer to the lot lines." They haven't made that revision yet... but I did find that in pointing this out the zoning / planning department during my application, they were willing to work with me to allow the heat pump to be much closer to the rear lot line than was allowed in their base rules.  Read more about their electrification here, the first linked report specifically: https://berkeleyca.gov/your-government/our-work/adopted-plans/berkeley-e...

  • Hi -- I'm hoping to get insights and recommendations from the smart group of people here.  I'm also hoping that sharing this information with quote amounts helps others and maybe also encourages others to move towards heat pumps.  Context -- My 22 yr old water heater should be replaced soon so I looked at replacing my furnace as well.  My home - 1400 sq ft on top flor with a 300 sq foot room on the bottom floor that is next to the garage and is built into the hill.  I wanted to zone the top floor separately from the bottom floor and got 3 quotes below and have included my electric and gas usage over the last year.

    Questions I have:  Do these look inline with current costs?  Though the warranties are for 12 years, how long should they last? I'm hoping that this will help keep my pge bills low -- any insights?  Is the technology where it needs to be or are advancements anticipated in the next few years?  What do people do when the electricity goes out?  Are there questions I should ask the vendors?  For rebates, etc. I've checked Bayren -- does anyone have thoughts about what new rebates we might get in 2023 and how to stay on top of newly available options?  I'm looking to move forward with the 3rd option but feel I need to do my homework if I'm going to spend that amt of money and hope that this amt of detail with quotes can help others.

    I greatly appreciate all help and recommendations!

    quote 1:  $20k after incentives/rebates.  dual fuel furnace and water heater -- not sure if this is truly better for the environment

    quote 2:  $30k for a single zone system. Equipment includes AMUG36LMAS Indoor. AOUG36LMAS1 Outdoor Fujitsu 36,000 BTU Ducted Minisplit 208-230V Inverter Heat Pump System Single Zone. R-410A.  Warranty: 12 years Parts, 5 years Labor SEER: 18 EER: 11.3 HSPF: 10.2 -- AND -- 50 Gallon Electric Hybrid Heat Pump Water Heater (DHW) 30AMP Ruud Professional Ultra PROUH50 3.55 Efficiency Warranty: 10 Years Tank, 10 Years Parts & 5 Year Labor

    quote 3:  $31k for top floor heat pump with a mini split for bottom floor supported by the heat pump.  Equipment included. Inverter Comfort System - 24 kBTU- Complete design and installation of a multi zone inverter heat pump. Mitsubishi* MXZ-3C24NA3 outdoor unit and SVZ-KP18NA air handler (located in place of existing furnace) and MSZ-GL09NA wall-mount for the downstairs bedroom. This unit will utilize existing ductwork   --- AND --  65 Gallon Heat Pump Water Heater (Bradford White) - Installation of a Bradford White self-contained heat pump water heater with a 65-gallon tank. Includes all necessary piping requirements including shut off and isolation valves, thermostat controller, and earthquake straps.

    My pge usage from the past year: 

    Electric:  ~350 - 450 kwh/month with 2 winter months at 625 kwh

    Gas -- 8months below 15 therms. 3m @ 30 therms and 1m@ 50 therms

    We recently installed a single zone 48,000 BTU Fujitsu heat pump and it was close to $14k. The contractor was able to use the existing duct system. I'm sure the contractor itemized the quote, so maybe you can compare the heat pump cost? 

    I love this question!! If you want someone else to run through this with you, you can contact QuitCarbon.com.  I found that they were not extremely helpful about subsidies, but they'll develop a sequenced plan for you and give perspective on the pricing you've received.  

    My fave source of information about the new climate bill's subsidies for heat pumps is the Rewiring America calculator: https://www.rewiringamerica.org/app/ira-calculator. For your situation, if you are moderate/low income you can get upfront discounts of $8k for the heat pump.  Couple notes about the upfront discounts: first, the income threshold might be higher than you think -- moderate income in the Bay for a family of 3 goes up to almost $200k.  Second, the upfront discounts won't be available til next spring or summer, because they rely on state programs to distribute federal money to contractors and retailers, so it takes a while to set up.   You may also be eligible for tax credits of 30%, up to $2k each for the furnace and water heater.  Those will be available starting 1/1/2023 and I believe you can just claim them.  They are *not* refundable, so if you use up your tax liability you don't get anything back, but I believe they can be carried forward to use in future years where you have tax liability. 

    They can also stack with the upfront discounts. Example: you are in the moderate income category and spend $25k on the furnace + $6k on the water heater.  You can get 50% off up to the limits as an upfront rebate ($8k for the furnace + $2k for the water heater), plus 30% as a tax credit up to the limits ($7.5k but limited to $2k for the furnace + $1.8k limited to $2k for the water heater).  Total savings: $13.8k.  

    The long term answer for when the electricity goes out is to have a battery backup + solar panels.  If you get the sizing right, you can make it through an indefinite outage with no problems.  

    If that's not currently in your budget, welll.... in the Bay Area missing heat/hot water is usually not dangerous. When we go electric, I plan to keep a gas camp stove around to use for bucket baths, cooking, and other emergencies if the power goes out.  (But we are in the flats near a hospital and rarely see outages.)

    In terms of costs, I recently got a quote for $16k for the furnace only component, but our home is smaller than yours. 

    Please feel free to message me if you have questions!  I am trying to organize a workshop for my neighborhood association, and if it goes well would love to export to other neighborhoods.  

  • Heat Pump with Radiant Floors?

    (3 replies)

    I’m wondering if anyone out here in eco Berkeley land has successfully installed a heat pump to run their radiant heating system. Currently we have a gas water heater that heats the water in the Pex in the floors. It seems like the larger HVAC companies don’t want to do anything that involves heat pumps and water systems. We have talked to a small shop who said he could do it but it seemed rather experimental territory. Wondering if anyone has done this successfully and has any advice or wisdom or recommendations to share? Thanks so much!!


    Yes, there aren’t a lot of companies offering this service. We’ve used this company and I do recommend them for install and repair. https://albertnahmanplumbing.com 

    We are in the process of investigating getting a heat pump to run our hydronic radiant system, and have talked to several contractors. There are some innovative companies producing heat pumps for use with hydronic radiant. The ones we know of are Harvest Thermal, Sanco, and FlowTech. Some of these are also "chillers" in that they can provide cooling via floors as well.

    As yet, it is hard to find contractors who are working with these brands because they are relatively new. Harvest Thermal seems particularly innovative but doesn't seem have many installers yet. The Sonoma Energy Center (run by Sonoma's utility) displays some of these brands of hydronic heat pumps. I hear East Bay Community Energy is setting up a similar site in the east bay but don't know when it will open.

    Once we find a contractor, we're looking forward to getting rid of an old gas boiler that powers our radiant (which is a combination of staple up PEX and embedded in slab), and using only our solar PV to run the heat.

    The old-fashioned HVAC people mostly seem to sell "ducted" heat pump systems (i.e., mini splits), which make no sense if you have radiant hydronic that you want to keep, as the whole point is that it is non-ducted and runs on water. You need a water source heat pump to run it, not an air source heat pump.

    Heat pumps are much more efficient that a traditional gas boiler. Separately from our existing radiant heating, we already have a heat pump water heater for domestic hot water and it saves a lot. If you have an older gas or electric water heater, you might also want to check out combining it with your radiant project. (Or you can get a domestic water heat pump separately - PG&E has rebates for domestic water heat pumps here: bayren.org).

    The new climate bill which will provide financial support for heat pump upgrades, and electric panel upgrades too. Rewiring America, a nonprofit, has an introduction to what kinds of tax credits and rebates here (most start after January 1): https://www.rewiringamerica.org/app/ira-calculator

    Another source of information about using heat pumps for radiant is Redwood Energy's manual here: https://redwoodenergy.net/all-electric-retrofits/

    Feel free to message me if you'd like to exchange ideas.

    My understanding with radiant floors is that if you run chilled water through floors, that can condensation on floor surface, which may not be great. Would love to find out your actual experience with selecting and replacing your boiler with a heat pump!

  • Hi! We've noticed an increase in moisture in our house since installing a heat pump (+ humidity outside has been higher lately) and have been advised to install a vapor barrier, which we know nothing about. Anyone have one recently installed? Any recommendations on who to reach out to whether this is the kind of project that warrants multiple estimates or can offer any other advice on how to proceed? Thanks!

    As a retired architect who has projects in many different climates, I can tell you this is a tricky question. 

    First, know that to install a stand alone vapor barrier means removing wall finishes—either exterior or interior depending on the climate. The vapor barrier should be installed on the warm side of the wall. In a climate such as ours, now that the climate is changing, there is no longer a typical warm side. If the vapor barrier is not correctly placed, moisture can be trapped in the wall cavity. Newer technologies such as blown-in solid foam insulation that provides both an air and vapor barrier address these problems.

    Best bet: contact three (or more) general or insulation contractors, ask what they recommend, and get an estimate for each. This will not be an easy or inexpensive project.

    Do you have mini splits or a ducted system? Our mini splits have a "dry" setting that takes moisture out of the air, which also cools it slightly. Wondering if this might help your issue?

  • Heat Pump?

    (6 replies)

    We are considering installing a Fujitsu 4 ton heat pump but we are limited in where we can place the unit. We are concerned about the potential noise and whether  it may negatively impact our enjoyment of precious little outdoor space we have. 

    Our only options are to place the unit by the living room window, next to patio or in front of a deck. All of these places are frequently used by us for all seasons. 

    I would love to hear about your experience with heat pump and how noisy it actually is. Thank you. 

    We got a Mitsubishi installed by Heirloom heating. Mike helped us with the ideal location on our house. It happens to be away from places that we hang out in the yard but it's near our trash bins so I'm out there frequently. It's very quiet. I've noticed the neighbors window AC is a lot louder than the heat pump. We got fresh attic and wall insulation around the same time and our house heats up quick and stays warm. The AC function is very cold and also seems to work quickly. From your description I would probably choose putting it next to the living room window. Even though it's quiet, it is bulky and blows out air. I wouldn't want to sit in front of it. We love love love our heat pump. You won't regret it. 

    We just installed a 3 ton heat pump ( mainly for AC) ~2’ under our redwood deck and can barely hear it when standing directly over it. We have to really listen for it otherwise don’t notice it. I’d say it’s less about the noise than the space it takes if your space is limited. Good luck!

    We have a mitsubishi unit that is very quiet. We installed it outside the kids' bedroom windows attached to the side of the house (2nd floor), and I was worried it would be noisy for them in their rooms but you really can barely hear it. The only time I do hear it is if three or four of the units are on at once, there is a bit of a hum when in the dining room as it's attached on the outside of that wall. This wouldn't be an issue for you if it is going to be installed on the ground. I would probably choose outside the living room window. If you would like to come take a listen to ours, PM me.

    Howdy folks,  I installed a heat pump driven ductless mini-split system a year ago.  My unit is only 1.5 tons, and drives two "head units" (the indoor, in-room blower units) to provide AC to two rooms (and heat, if desired).  So not an apples-to-apples comparison, but my 1.5 ton unit doesn't create a lot of noise.  When both inside blowers are running on AC, at about 1/2+ fan speed, the sound of the outdoor compressor is like a floor-stand fan, just a white noise sound of blowing.  There's no rumble or engine sound, just a sound like a running fan / air blowing sound.  Totally aware this isn't a perfect comparison to a 4 ton unit which may be cooling an entire house, but there it is.  Best of luck.

    The decibel rating can be found in the specs - look up the particular proposed model, and you will find the dB rating. 

    But I'm wondering who suggested a FOUR - ton unit!  That's really huge for Berkeley.  Unless you have a huge home, and/or it's really badly insulated (in which case, remedy that, first),  you might want to get a few more folks to come give proposals.

    I am the OP. Thank you everyone for your feedback. We finished installation and I am happy to report that it is quiet when running the AC and much more quiet than our old gas powered HVAC system. We will see how the heating sounds. Thank you!

  • Hi All,

    Since installing our new heat pump about 8 mo. ago, we're now finding we have a mold issue that we have no idea how to cope with. We've seen signs of mold in three closets (along the baseboards and destroying a few clothing/cloth-covered items, in spite of keeping Damp Rid bags and leaving them constantly open to ventilate. More recently, I've had to toss an old book on an open bookshelf covered in white mold and found a few days ago a fuzz of mold on a basket also kept out in the open. So our mold issue extends beyond badly ventilated areas. I'm trying not to (fully) panic yet, especially with two small kids in the house, but what do we do?

    The heat pump settings are such that we can't run the dehumidifier function AND heat (dumb). Is there a better solution than running multiple de-humidifiers in several rooms at all times? Do we need to hire mold cleaners (who quoted one tiny closet measuring about 5x5' several months ago at $1,500+) as part of this? Is anyone affordable? Is there someone we can consult for structural changes that would reduce/eliminate the likelihood of mold throughout our house?

    What do we do? Heeeeeeeeelp!!

    It's hard to imagine a heat pump would have a significant impact on mold--especially in our climate--unless its drain were not configured properly or you had a water leak or something. Try opening windows during the day?

    A heat pump dehumidifies by (essentially) cooling the air, so that's why it can't both heat and cool at the same time, though I suppose you could do so by turning it to dehumidify and using space heaters, which would be cheaper than dehumidifiers.

    Measuring the humidity in various places is important--you can buy hygrometers off Amazon or another site for super cheap ($5 or so).

    If the humidity is high, you have to figure out where it's coming from and fix that. 

    Using an ozone generator (for use only in UNOCCUPIED SPACES) would definitely help with killing mold, but you really have to find/ fix the water source first. 

    I'm so sorry you are dealing with mold. It is truly insidious and can cause major health issues - so it is no joke. It needs to be dealt with properly or it can cause more issues down the line. When we were dealing with a similar issue, we researched companies and found Anderson Group International out of San Jose. They were recommended to us by multiple Water-Damaged Building experts. Repairs and remediation will be costly: you will need to address the cause of the mold, remove all affected materials, decontaminate, then repair. Please call them to help you. This is truly not something you should tackle on your own and ideally, you don't even want to be living in a home with that degree of infestation.

  • There are a few older postings on this, but I wondered what the latest information might be.  We live in a 30 year old condo with a forced air gas furnace in the attic, and want to switch to a heat pump.  We would love advice as to what is involved (e.g., do we need an electrician involved to also run higher voltage in), and even better, who we might trust to do it for us.  We're trying to be more energy efficient and all that, our gas furnace is aging and replacing it with another gas furnace seems climate unfriendly.

    Thanks a lot!

    [moderator note] Here is a recent discussion about AC that recommended heat pumps: Seeking alternatives to installing central AC

    My family needed to replace our furnace and went with a heat pump because we expect within the lifetime of any furnace/heat pump, air conditioning would become more and more necessary due to climate change. A heat pump was cheaper than furnace+AC and is better for the environment (and our electric bills now are pretty similar to our electric+gas bills before; just be sure to let PG&E know you’ve switched to electric heat so they raise your baseline for Tier 1 electric usage). You likely will need an electrical upgrade (we didn’t because by chance we had an extra electric panel in our house that we weren’t using). We went with Lennox through Costco. Their price was a bit higher than other vendors we talked to, but we got a huge Costco credit as cash back, and their system was much bigger (other vendors quoted us for heat pumps for our whole house that are meant for just a single room, which honestly is probably sufficient in the Bay Area). In the end, I’m very happy with the decision because electrification is an important climate change mitigation, and now we have AC!

    Hi Momima!  I work in the field of home efficiency and electrification and recommend checking out The Switch is On website (https://www.switchison.org/get-started) as a great resource to get started with this project -- you can look up contractors who are experienced with heat pumps and see the incentives that are available in your area.  We worked with Electrify My Home (https://www.electrifymyhome.com/) and are very happy with our system.

    I switched from old gas space heating to heat pump (also replaced my water heaters and turned off the gas!!!)

    Be sure you get a company that has experience with heat pumps.  The system(s) need to be designed for YOUR home layout.  I ended up with two separate systems for my 3 floor hillside house; one compressor for a mini-split ducted system for the middle floor and a wall unit for the basement.  The other compressor connects with three wall units for the top floor.  It was not cheap, but the result has been GREAT-- excellent heating, and the pleasure of having air conditioning.  Also no more outrageous gas bills.  The heat pumps are so efficient that my electricity didn't go up much. (Not true for my electric vehicle...) I used A1 Guaranteed in Sonoma. 

    I just got an email from East Bay Green Home Tour about a webinar on Oct 6:

    Dreaming of Air Conditioning, Replacing a Furnace, or Remodeling?

    Adapt to Climate Change with a Heat Pump! 4 East Bay Neighbors Show Their Heat Pump Systems.

    Register:  https://www.eventbrite.com/o/east-bay-green-home-tour-32572642533https:/...

    In this free, one-hour webinar, four East Bay neighbors will show and tell you about their heat pumps: energy-efficient systems that can heat, cool, and filter indoor air. Heat pumps can help you adapt to the hotter, smokier future we are facing, while also moving you off natural gas, which drives climate change. The four homeowners – plus heat pump expert Kyle Bosworth from EcoPerformance Builders – will respond to your questions about their heat pump systems, including ducted and ductless. Brought to you by the coordinators of the Bringing Back the Natives Garden Tour and the Green Home Tour.

  • We are considering replacing our central gas furnace with a ducted mini-split heat pump and wanted to hear how others' experience with ducted heat pumps has gone.  Does it provide enough cooling on the occasional hot summer days?  Is it noticeably noisier than a gas furnace?  

    We had a mini-split system in Brooklyn and it was excellent. Much quieter as the only fan that's on is the one that's in the room that needs the cooling. Our condenser unit was on the roof and we never heard it. Definitely provides enough cooling - though you need to have it sized for your building. I'd say it's far quieter than a gas furnace as you don't hear it click on, or the whurring of the wind through the ducts themselves.

    Which one were you considering specifically? Did you mean Ductless instead of Ducted?


    We installed a ducted Fujitsu heat pump system in our house (1400 sq ft) last year and are very happy with it!  It is not noisier than a gas furnace: I believe the fan/blower system is just a standard fan system, no different from the one that would circulate air heated by a gas furnace fire.  The compressor outside is as loud as an air conditioner (because a heat pump space conditioning system is basically an air conditioner with a reversible valve, allowing it to both heat and cool).  The compressor is outside our kitchen window and I don't notice the noise unless I'm listening for it (it's only running sporadically anyway, just like an A/C).  It keeps our house very comfortable, and also feels good to know that no longer burning gas is the right decision for the climate and air quality in general.  We like being able to pre-cool/pre-heat our house at times of day when there's excess solar on the grid.  It's a great decision, especially if you were considering installing/replacing air conditioning anyway.  BayREN may be able to connect you with rebates depending on where you live.  Feel free to reach out to me directly if you have further specific questions!

    I have a similar question!  I have a bid for a Mitsubishi pump with ducts for heating and cooling for our downstairs and minisplits for our upstairs bedrooms but it is quite expensive.  The system also requires an electrical upgrade.  Does anyone have experience with this sort of heating and cooling system? Thanks!       

    We installed a ducted mini-split heat pump in our house a few years ago.  We don't use the AC that often - probably a few days a year - but it is nice to be able to cool the house on those occasional days that are hot enough to warrant it.  (If it's only moderately warm we just use fans to save energy.)  We have not had any issues with cooling capacity.  It's worth noting, though, that the airflow from a heat pump is less powerful than from a furnace, so a cold room will heat less quickly than it would with furnace.  I assume the same would be true for cooling, but we've never had traditional AC to compare to.  Using a thermostat set point or scheduling it to come on in advance solves that problem.  We actually find that, with a gentler air flow, the heat pump is significantly quieter than a furnace.  We don't notice that it's on other than the house being a comfortable temperature.  The outdoor unit makes some noise, but it's not noticeable inside our house.  Overall, we've been happy with our heat pump.

    I can’t explain the mechanics of heat pumps but I can tell you my experience with ours. The noise is very similar to a furnace or air conditioner. It takes much longer to heat or cool your home so you want to want to turn it on before it gets too hot or cold. I have been told they are efficient. 

    We have a heat pump and love it.  We have one Fujitsu mini split wall unit and one ducted for our 1000 sq ft home and the ducted unit works better and is silent (quieter than a gas furnace for sure).  It also cools really well.   We've had it for about 6 years and super happy. We used Kevin Armstrong https://www.yelp.com/biz/specialized-heating-and-air-conditioning-castro... who did a great job and was far cheaper than the other 2 companies we got bids from.  In 6 years, we've had just one minor issue and Kevin came out on the same day (a Saturday!!!) to fix it. 

    We've have a ducted system  for 2 years and much prefer it to our old gas furnace for heating. It blows more gently and more moderately heated air so you don't get the temperature swings like with a furnace where it blows HOT, then stops and the house cools off (probably more quickly than it should with our old single pane windows), then HOT again. The fan noise is very quiet  (much quieter than the furnace) and so is the compressor--ours is pretty big and we never hear it (I think we set it up on some optional vibration absorbing pads). We have not used it much for A/C yet but now that we have MERV 13 filters, I think it will be helpful on hot, smoky days when you can't have windows open (new normal, sigh).

    One thing I don't like is the thermostat. It's even "dumber" than a basic furnace thermostat in that you can only set it in 30 min increments (instead of 15), it doesn't show current temperature, and it's hard to program. I think there is one other that I'm not remembering right now since I haven't used it since the Spring. It's more of an annoyance than anything else, but I'm curious, have other posters on this thread upgraded their thermostat to a Nest or anything else? I actually don't need a smart one, I just want an easy one. I feel like heat pumps can't use regular furnace thermostats but I could be totally wrong.

  • We need to replace our heating system and are looking for any recommendations for heating companies that install high efficiency heat pump systems.  If you have had one installed and are happy with the work and price, it would be wonderful to hear your experience (and the cost!). 

    Thank you!

    We just got a bunch of quotes and are currently installing a mini-split system with A1. Their proposal was the most cost competitive and they are very active in the decarbonization community. May want to contact the BayRen nonprofit as well for additional recommendations, they have been helpful.

    Great that you are considering a heat pump!  I work in the field of building electrification (policy, not the technical aspects) and this transition is so important for our climate!  I am in the middle of having a ducted mini-split heat pump installed in my house.  Our system was sold to us by Larry Waters at A-1 Guaranteed and I found him very knowledgeable.  We also got a quote from Hassler but didn't like their proposal as much because they recommended individual heat pumps in many rooms, rather than a ducted system (which we prefer for aesthetic reasons).  If you already have heating duct work in your house (we don't) Hassler may also have a good idea for your house.  The quotes were comparable.  Unfortunately I can't report on the work because the install hasn't started yet! 

    You may know this, but after completing the project be sure to contact PG&E to get on their "all electric" rate (you can still have gas cooking/water heating to qualify).  This will increase your Tier 1 allotment and reduce system operating cost. 

    Good luck! 

Parent Reviews

We swapped out our ancient gas furnace for an electric ducted mini split system and got quotes from a few installers and Hassler was definitely the most expensive.  We went with Kevin Armstrong who is a solo practitioner (chis ompany name is Specialized Heating and air conditioning (510) 886-5853). Kevin was recommended by the minisplit distributor company who told us that Kevin is the guy they call when people's mini split systems are installed incorrectly and Kevin fixes them.  He did a great job, was inexpensive and when we had a problem several years later, he came over on a weekend and fixed it quickly. We didn't have heating ducts prior to installing the mini split, so Kevin did all that duct work.  Six years later we're totally happy with what he did.  (And he was probably 30% -40% less than Hassler).

Atlas heating and cooling installed our mini split system. Reliable, good communication, good work and follow up when we had a few minor issues while it was under warranty. System is working well. I think the price was fair, too.

I’m having a Mitsubishi mini-split system installed right now, for just the two upstairs bedrooms. Cheapest quote from reputable installer (Nahman) was $18k. Others ranged up to $22k. I’m having ducts installed in the ceiling (from the attic space), rather than those big wall units, which I hate. But price is not much different for either. Mini-splits do both heating and cooling, meaning I could get rid of the baseboard heaters in those rooms, which is also nice. 

We've been getting estimates for a heat pump to replace our gas furnace, which would also provide cooling for "free" (the heating process is just reversed).  The mini split is a heat pump for one room only - you see them in hotel rooms mounted under a window or high on the wall. They are getting more popular and easier to find. Most of the major plumbing and HVAC companies can give you an estimate to install a heat pump or mini split now. As renewable energy becomes cheaper and more available, electric heating is going to be a lot cleaner than gas, and some cities like Berkeley are starting to ban natural gas in new construction. So electric heat pumps are the way to go for the future.

The City of Berkeley recently co-hosted an online "Green House tour" of local homeowners who have installed various appliances that don't use natural gas, including heat pumps, induction cooking, clothes dryers, etc. It's really informative - there is a video of one family in Lafayette that installed mini-splits in every room along with lots of other eco features. In all the videos, the owners walk you through their house explaining what they did, and why, how much it cost, who their contractor was. There is a list of the houses here: https://www.eastbaygreenhome.com/sites  - click a house to see what brands and contractors they used. To view the videos of each house, go on youtube and search "east bay green home tour"

We live in a 1500 sf house and just got our entire HVAC system replaced with heat pump system that takes advantage of the mild climate here to provide heat and cooling without relying on gas (all electric). It cost $16k, including entirely replacing the duct system in the house. Let me know if you want the name of our contractor.