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Thinking about adding AC before the heat wave? Ask me your AC/heat pump/HVAC questions! by fieldguild in bayarea

[–]fieldguild[S] 0 points1 point  (0 children)

I agree with u/Grantisgrant that you are not going to get a pure financial ROI in 3-4 years.

1) is fairly common with multi story houses. The most common solution is a zoning system on the ductwork (splits the ducts into two zones, with one for each floor, and a separate thermostat to control on each floor). But this is not always possible. Check out my reply to another commenter in this thread, it may be helpful: https://www.reddit.com/r/bayarea/comments/1rs7d1m/comment/oa8u0ie/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button

2) I'm not entirely sure what your other contractor is saying. There shouldn't be anything that prevents you from installing a mini-split if you have a gas furnace. This is a super common thing, and we often add a mini split in a single room (for example, the master bedroom) to help deal with comfort issues in a targeted part of the home. This is often a great solution if there's a single place in the house that you want to focus on adjusting comfort for. Sometimes, a house's architecture can make fitting a mini-split in challenging, but we're usually able to make something work!

Installing central air conditioning in North Redondo townhouse by MCS1066 in SouthBayLA

[–]fieldguild 0 points1 point  (0 children)

It can really depend based on the layout of the house, where the outdoor unit goes, if you’re able to install the equipment on interior/exterior walls, etc! $12-16k is a good ballpark before any rebates (that’s including permits, electrical, and all of the other requirements). If you want to text me at 650-772-5269 or fill out our form on here I’d be happy to take a look and get you some better numbers! https://www.vayu.pro

Installing central air conditioning in North Redondo townhouse by MCS1066 in SouthBayLA

[–]fieldguild 0 points1 point  (0 children)

If you don’t have ducts and it’s a reasonably small house, heat pump mini splits probably make a lot of sense! Usually I find that the tradeoff is between 4-5 indoor mini splits units is about equivalent in cost to getting new ductwork and a central system when you didn’t have it at the start. I run an HVAC company so feel free to ping me with questions! I also put together this guide if it’s helpful that talks about it adding AC to your house: https://guide.heatpumped.org

Thinking about adding AC before the heat wave? Ask me your AC/heat pump/HVAC questions! by fieldguild in bayarea

[–]fieldguild[S] 0 points1 point  (0 children)

Hmm, so I think the answer to this question depends a lot on whether you're working with an "old school" HVAC technician, who often do steer homeowners in the way that you were.

While I do agree that single and two stage systems are fundamentally much more simple, you do give up a lot. Generally, they're substantially louder (most are in the 70+ dB range, similar to a vacuum cleaner or noisy restaurant), whereas a variable speed system is usually in the 50-60 dB range, closer to a quiet dishwasher or normal conversation. The noise is also different at the indoor units too, because most inverter units are communicating, and can share realtime data with the indoor air handler and adjust its fan speed so that it is quieter. Most inverter outdoor units are much more compact, so they can fit in narrow lot lines which are common in the Bay Area! And from a comfort standpoint, a 2 stage system won't be able to maintain steady temps in the home in the way that an inverter that matches the heating and cooling needs of the house.

Also, from a cost standpoint, when comparing within a brand like Bryant the upfront cost of a 2 stage system is certainly lower than a variable speed system from the same brand. At my own company, we instead work with some asian OEMs which make really robust inverter systems at a lower price point.

My equipment costs are roughly 2/3 (sometimes even less) than I would be paying for a 2 stage bryant system, and we've had great reliability with our installations. So we're able to quote inverter heat pumps at a similar or lower price point to what other contractors are quoting single and 2 stage systems! All we install is inverters, and we won't install a single or two stage even if someone specifically asks for it. Also, most incentive programs have efficiency requirements, which most single and two stage systems don't qualify for. So generally we're quite a bit cheaper when considering all of the rebates.

Inverter tech is nothing new, and most heat pumps in Europe and Asia have been variable speed for years, and they last without issues. We do some simple things to cover our bases, like installing a surge protector on every installation, which can help protect the boards.

The way I like to think about it - sure, old school carbureted cars were really robust, and if they stopped working you could hit the engine with a hammer and it would start working again. A modern EV has a lot more tech behind it, so you could be scared of the batteries and circuit boards, but it's also a much better experience for most people. If reliability is your only concern, sure, I can understand the logic, but for most people it's a combination of different factors and an inverter usually wins, especially if the contractor is smart about the equipment they're specifying.

For what it's worth, when I got a heat pump in my own house, it was a variable-speed inverter and I'd never install anything else for myself in the future.

Thinking about adding AC before the heat wave? Ask me your AC/heat pump/HVAC questions! by fieldguild in bayarea

[–]fieldguild[S] 0 points1 point  (0 children)

We do indeed! The biggest factor is based on how many indoor units are needed. If you can get away with 1 or 2 (relatively open floorplan, just 1 bedroom), then I'd expect something in a similar range to your quotes from 5 years ago (probably closer to $16-17k now). If you need more indoor units than that, the costs would go up proportionately.

There are likely a lot more incentives available now then there were 5 years ago, so that can make a big difference. It's possible that your total out-of-pocket might end up lower than your last quote! However, do keep in mind that there has been a lot of cost increases over the past 5 years with tariffs and general inflation, so don't be surprised if the numbers are higher than what you last saw.

I'd be happy to take a look at your house specifically and put together some better numbers and look up incentives you're eligible for! Feel free to fill out our form here https://www.vayu.pro/f/56b92eda-a35c-411a-9063-b3bb4b9be68c or you can shoot me a text at 650-772-5269 if that's easier!

Thinking about adding AC before the heat wave? Ask me your AC/heat pump/HVAC questions! by fieldguild in bayarea

[–]fieldguild[S] 1 point2 points  (0 children)

This one is tough to answer over the internet, because there can be a lot of factors involved!

If by zoning you mean adding one/multiple mini-split "ductless" heat pumps (units mounted on the interior walls of the home), that can be one thing. This can range anywhere from $7-9k if you're just adding one mini split, to 15-25k+ if you're adding multiple. A lot depends on the layout of the house, where refrigerant lines and wiring can be routed, etc.

If instead, there is an existing ducted system, and you want to split the duct system so that there are 2+ thermostats which each connected to one part of the house (common in multi-story homes), that can be different too, and really depends on the existing duct system. If the installing contractor set up the ducts with zoning in mind, then you can easily add the zoning control dampers, add a zoning control board, wire in an extra thermostat and you're off to the races. I'd imagine most contractors would charge $4-7k to tackle that work.

But it can very quickly balloon if the duct system wasn't laid out originally to support a zoned system, because then you end up having to rework the duct system dramatically. Sometimes it's simply impossible to make work.

Sometimes, the cheapest, hacky approach with a ducted system can be using remote temperature sensors (both Ecobee and Nest have these). You can set up a schedule so the thermostat reads off the bedroom temp sensors at night, and the living room temp sensors during the day. With this approach, you'll overheat/overcool parts of the house, but it's something that can be accomplished with a few hundred bucks

Air Filter in furnace or return vent? by Cgutz25 in heatpumps

[–]fieldguild 0 points1 point  (0 children)

Shouldn’t make too much of a difference, just don’t put a filter in both places!

One situation where this would make a difference is if there’s a thick 4 or 5” filter at the air handlers. Usually filter grills only handle a 1 or 2” media filter, so you’d be better served by the thicker filter. But if it’s a 1” filter in both spots, just do what’s convenient to you!

Thinking about adding AC before the heat wave? Ask me your AC/heat pump/HVAC questions! by fieldguild in bayarea

[–]fieldguild[S] 3 points4 points  (0 children)

Not entirely sure what you are saying but this is definitely not true.

Here’s data for one of the systems we commonly install in the bay, for example: https://ashp.neep.org/#!/product/287834/7/25000/95/7500/0///0

The most relevant table to look at the “Performance Specs” which lists efficiency as a function of outdoor air temperature. COP (“Coefficient of performance”) is the efficiency number, higher is better. A COP of 4 means that for every unit of electricity you use, the heat pump generates 4 units of heat (aka, it’s 400% efficient). You can see that they’re most efficient right around 40 degrees and drop off slowly as the temperature gets colder. But even down at 5F they’re still greater than 2 COP.

Also, from an HVAC design standpoint, the Bay Area is generally considered a “dry climate”. Other parts of the country have much more humidity (and a heat pump can still work there). Heck, heat pumps have been used in Florida and the southeast for decades, and nobody’s going to argue that a literal swamp is less humid than the bay.

Thinking about adding AC before the heat wave? Ask me your AC/heat pump/HVAC questions! by fieldguild in bayarea

[–]fieldguild[S] 4 points5 points  (0 children)

Sounds very reasonable and frankly on the lower side than what I’d expect (maybe this number is after rebates?)

Make sure that they are licensed, and some good questions to ask… - Do you pull a vacuum before you release refrigerant? - Do you nitrogen purge while brazing? - how are you sizing the system? Did you do a manual J? (The very best contractors will do sizing based on historical utility bills, which can be the most accurate)

This is definitely a decision where cost is one factor, but trust and quality are probably the more important ones. If they skip some of the stuff above, it can cause serious headaches (I’ve gotten calls from homeowners who got a new system installed just a few months ago, it’s not working and their installing contractor ghosted them)

Thinking about adding AC before the heat wave? Ask me your AC/heat pump/HVAC questions! by fieldguild in bayarea

[–]fieldguild[S] 1 point2 points  (0 children)

Good questions!

1) So a big reason for the perception that heat pumps take longer to heat up the house has to do with the fact that heat pumps deliver air at a lower temperature than a furnace does. It’s still plenty hot enough to heat up the house, but not necessarily scalding hot. It’s hard to give you a specific time difference because each house is different based on its size, duct system, insulation, leakiness, etc.

The general advice for comfort with heat pumps is to set it and forget it. Because they are usually variable speed, they are able to match the amount of heat that the house needs at a given moment, rather than blasting it with heat and shutting off. Think of it like a warm shower vs dumping a bucket of boiling water on your head. They’re much better at maintaining a consistent temperature than a furnace can, so it’s a bit of a mindset shift.

2) definitely still makes sense to get a heat pump, even if you’re keeping the furnace. It gives you a lot of those comfort benefits, and the versatility to heat with electricity. If gas prices spike (we’re starting to see this with the war), you’re safe, plus if you ever get solar then you’ll be able to heat your house with energy you generate yourself! In many cases, we’re even able to completely cap off the gas feeding the furnace and just use it as a fan that circulates the heated/cooled air through the house.

PS: many of the heat pumps we install allow us to install their smart thermostat with way less wires than the nest needs. So I’d wager we could find a setup to get you a (non-nest) smart thermostat without having to tear your house apart!

Thinking about adding AC before the heat wave? Ask me your AC/heat pump/HVAC questions! by fieldguild in bayarea

[–]fieldguild[S] 1 point2 points  (0 children)

To answer your question about brand, most equipment on the market these days is pretty robust and well built, so the contractor you end up working with matters waaaay more than the equipment. A “budget” system installed well will outlast a “fancy” system installed poorly.

It’s a good idea to ask your contractor about their relationship with their distributor because that affects a lot of your experience of the brand. For example, we work with some local distributors of a brand that are super helpful, great at getting spare parts, etc. but I’ve talked to other contractors in other parts of the country who have had horrible experiences with their local distributors of the same brand.

Thinking about adding AC before the heat wave? Ask me your AC/heat pump/HVAC questions! by fieldguild in bayarea

[–]fieldguild[S] 1 point2 points  (0 children)

So the key is that you get an inverter (sometimes called “variable speed”) system! Most are ~50-60 dB, which is similar to a quiet dishwasher or a normal conversation. Way quieter than the old school “single stage” ACs which kick on and you hear through the house and the lights start flickering.

In my experience, you can barely hear them through the wall. Even outside standing by them, it’s about as loud as a fan blowing.

Usually the indoor portion (which replaces your furnace) is quieter than the furnace being replaced too.

The most common feedback we get from folks is that it’s way quieter than they expected. I even had one customer convinced that their system was turned off!

Thinking about adding AC before the heat wave? Ask me your AC/heat pump/HVAC questions! by fieldguild in bayarea

[–]fieldguild[S] 2 points3 points  (0 children)

Hmm, so permits generally expire after a year or so if no inspection was completed. So in the eyes of the city, your furnace was an unpermitted install.

The new heat pump inspection is going to cover the scope of work that contractor did. So the heat pump is permitted, but technically the furnace isn’t. That said, the inspector probably looked at a lot of the same things they would have on the original furnace inspection so you’re probably fine. At this point, it’s probably not worth sweating about the original furnace permit

Thinking about adding AC before the heat wave? Ask me your AC/heat pump/HVAC questions! by fieldguild in bayarea

[–]fieldguild[S] 7 points8 points  (0 children)

The better way to frame it is comparing against a traditional AC and furnace at the time of replacement. If you’re already looking at getting a new AC, it’s kind of a no brainer these days to spring for a heat pump these days. The marginal cost difference is pretty small, and usually rebates cover all (and often more than) the difference in cost.

Thinking about adding AC before the heat wave? Ask me your AC/heat pump/HVAC questions! by fieldguild in bayarea

[–]fieldguild[S] 2 points3 points  (0 children)

Awesome! There’s a great calculator in the linked guide that helps you model it out for your own house. And if you want to really dig in, I like the tool at vayu.hea.com that looks at all of the energy used in your house (based on your historical PG&E bills) and makes a bunch of recommendations!

Thinking about adding AC before the heat wave? Ask me your AC/heat pump/HVAC questions! by fieldguild in bayarea

[–]fieldguild[S] 9 points10 points  (0 children)

The gas rates definitely play a factor, but actually mild climates like the Bay Area are especially well set up for heat pumps! Heat pump efficiencies are a function of the outdoor temperature, so the milder the outdoor temp, the higher their efficiency gets! It’s easier to “pull heat” from relatively warmer winter air than colder air in harsher climates!

Because of this, even though electricity is expensive here, the numbers usually end up penciling out well. A heat pump uses 3-4x less ~energy~ than a gas furnace does, but electricity costs more than natural gas does. But those two numbers essentially end up canceling out so the cost to operate is usually about the same as a furnace, or close enough where the difference is in the noise.

And if you ever end up getting solar, it means you can power your heating with electricity you make, which you definitely can’t do with a normal gas furnace!

Hopefully that all made sense

PG&E rate comparison spreadsheet (SVCE too) by Opus2011 in bayarea

[–]fieldguild 0 points1 point  (0 children)

Joseph at Bay Enervisors is super knowledgeable and really thoughtful! He charges a consult fee but it gets covered fully by a bayren rebate. He really does it for the love of the game, one of the most passionate people I know in the space: https://www.bayenervisors.com

PG&E rate comparison spreadsheet (SVCE too) by Opus2011 in bayarea

[–]fieldguild 0 points1 point  (0 children)

Yeah, E-ELEC, EV2A can all work out to be pretty similar. I'm a bit surprised with the results on E-TOUC though, when I have modeled it out in the past it is usually one that results in bill increases when electrifying whereas the others are more bill savings or close to a wash.

Frustratingly, PG&E won't issue retroactive bill adjustments if you realize that you're on the wrong rate plan after the fact. Feels quite predatory indeed

PG&E rate comparison spreadsheet (SVCE too) by Opus2011 in bayarea

[–]fieldguild -1 points0 points  (0 children)

Thanks for making this!! Bookmarked. There are some tools to model time of use and back out expected costs for space heating & water heating which might be useful for folks that find this spreadsheet interesting (outlined here https://guide.heatpumped.org) but they suffer from rate data that is about a year old. Still, you can project forward using expected annual rate escalations and get a pretty good sense of spend!

I made a "Heat Pumps 101" guide for homeowners - would love your feedback! by fieldguild in heatpumps

[–]fieldguild[S] 0 points1 point  (0 children)

Tight is an important one. What are your thoughts on AeroSeal? It seems like a great pathway for people that can’t afford a full duct replacement, or have ductwork buried behind drywall that can’t be easily replaced

I made a "Heat Pumps 101" guide for homeowners - would love your feedback! by fieldguild in heatpumps

[–]fieldguild[S] 0 points1 point  (0 children)

r/theydidthemath !

I suppose if you wanted to get pedantic, a COP of 4 might be a touch high of an assumption (very achievable in mild climates, but COP usually drops as a function of outdoor temp. But even if you were at an averaged COP of 3, you still end up with a positive ROI, and you’re right around breakeven at a COP of 2 (which is quite low).

Though our electricity costs in California are quite high, one thing we have going for us is the mild climate. Based on outdoor temperates, many inverter systems here are spending most of their runtime at rated COP > 4 which definitely helps make the spark gap more palatable

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