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Launch HN: Electric Air (YC W23) – Heat pump sold directly to homeowners

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Re: Launch HN: Electric Air (YC W23) – Heat pump sold directly to homeowners

#491

Post by tguvot »

criddell wrote: post #484
tguvot wrote: post #464

Earlier quoted context omitted.

actually i'll advise you to take a look at temperature of your walls. both inside and outside. they have a bunch of thermal mass. during the summer they effectively heat the air inside the house. unless you manage to cool walls somewhat (lets say during night), hvac will have to really fight to keep temperature down. I live in bay area and I installed whole house fan which is typically runs through the night at summe…

Our walls are good but our windows are a weak point. During summer, the night temperature drops to the low 90’s here. It’s A/C all day, every day, for at least 3 months. Any idea why the HVAC guy and just about every source online insists that A/C can only give you a temperature delta of 20F? I know it can’t be true, but that claim is everywhere.

>Our walls are good but our windows are a weak point.

are you sure ? at summer I have walls that are 170F outside (at 2pm) and 80-90F inside. Also, window will pass through heat only during the day. Wall will keep heating your inside air through the night as well. Get some cheap thermal camera - it's very educational.

You should also check your ductwork/registers. To see if there are any tears/openings/etc. Also, in case you are using flex duct, if it's not tensioned properly, sagging, etc - there will be a lot of air velocity losses that reduce overall cooling experience.

>Any idea why the HVAC guy and just about every source online insists that A/C can only give you a temperature delta of 20F? I know it can’t be true, but that claim is everywhere.

Something around refrigerant properties, mechanics and physics, etc. I also spent some time in this rabbit hole

Re: Launch HN: Electric Air (YC W23) – Heat pump sold directly to homeowners

#493

Post by faefox »

lazyasciiart wrote: post #466
cmui wrote: post #381

Earlier quoted context omitted.

I like the out of the box thinking! Unfortunately I think this one doesn't quite pass first principles. Any pumping action from the vehicles would be extra work they have to perform, so you just shuffle the energy expenditure from your local heat pumps, to a fleet of vehicles.

Aren’t the cars already performing that work, just letting the energy dissipate into the road surface instead of going somewhere?

It takes more energy to drive a car through mud than on pavement. The same principle would apply here.

Re: Launch HN: Electric Air (YC W23) – Heat pump sold directly to homeowners

#494

Post by sokoloff »

nerdface wrote: post #293
cmui wrote: post #123

Earlier quoted context omitted.

My hats off to you for doing a DIY install. This is not a bad route to go if you enjoy/feel comfortable doing the work and don't care about air quality, smart thermostat integration, etc. Re contractors, we will have local contractor partners do the install and handle servicing, so you won't be left with an unserviceable system.

> This is not a bad route to go if you enjoy/feel comfortable doing the work and don't care about air quality, smart thermostat integration, etc You're insinuating that doing the work yourself means you'll have poor air quality, poor thermostat integration etc. That's not true at all. If you've gone to the trouble to do a DIY install then you're now already experienced enough to install a heat-recovery ventilator to…

Reading their comment slightly overly charitably vs what was written (but almost surely in-line with what was intended), they were contrasting their unit that has a HEPA filter bundled as part of their unit and that is not part of the Mr Cool unit.

Re: Launch HN: Electric Air (YC W23) – Heat pump sold directly to homeowners

#496

Post by tedivm »

cmui wrote: post #88
daredoes wrote: post #76

Earlier quoted context omitted.

Would your company be willing to provide an open-source local-first websocket-based integration with https://www.home-assistant.io/ or use the new Matter + Thread standard to provide it for everyone? If that's available, this would be my top choice as I'm actively shopping for all-electric heat pumps

It's something we'd definitely consider. Is the desire to have thermostat control via any third party? edit - The current plan has been Matter/thread Homekit + Google Home integration. We can expose at least temperature control via this to everyone.

If you support home assistant then I am far, far more likely to purchase this. My wife and I are buying a house sometime over the next year and one of my higher priorities is getting a heat pump. At the same time though I also refuse to use cloud based services and instead prefer to run my own home assistant installation.

You should consider this a huge marketing opportunity- the home assistant people are obsessed with perfecting HVAC (half of these people have their own weather stations) and are also the kind of geeky first adopter who will push useful tech on all their friends. It's also not a small community, as the subreddit alone has over 222k people on it.

https://old.reddit.com/r/homeassistant/

Re: Launch HN: Electric Air (YC W23) – Heat pump sold directly to homeowners

#498

Post by sokoloff »

turtlebits wrote: post #216
criddell wrote: post #202

Earlier quoted context omitted.

We had a mini split installed into our garage (a Daikin that’s been great). I’m not sure how we would do that for the house. It’s a forced air system with outlets and return air in every room. I’m not sure how feasible it would be to pipe the output from a split system into that ductwork.

Mini splits aren't ducted (generally the air handler is mounted high up on a wall). They are great for spot heating.

Ductless mini-splits aren't ducted. (These are the type most are familiar with, the ones with a large air handler up on the wall or in a ceiling cassette.) However, mini-split just means that the condenser and evaporator units are separate ("split") and are smaller capacity ("mini") than a traditional central air system (which are also "split").

There are ducted mini-splits in addition to ductless mini-splits.

Re: Launch HN: Electric Air (YC W23) – Heat pump sold directly to homeowners

#499

Post by sfink »

lazyasciiart wrote: post #466
cmui wrote: post #381

Earlier quoted context omitted.

I like the out of the box thinking! Unfortunately I think this one doesn't quite pass first principles. Any pumping action from the vehicles would be extra work they have to perform, so you just shuffle the energy expenditure from your local heat pumps, to a fleet of vehicles.

Aren’t the cars already performing that work, just letting the energy dissipate into the road surface instead of going somewhere?

No. The cars would be doing a little extra work. Imagine if you did it with half-filled hoses of water going in a loop. The car tires would be pushing the water through the hose, adding drag. The energy cost would come from the gas or electricity of the car.

It's like the usual analogy I used to use for content mills or adtech: it's like setting up wind farms along the interstates. The wind from the trucks creates free energy! Awesome, right? Except that those trucks are no longer drafting off each other quite as much...

(And I say "used to use" because it used to be a small tax, a bit of an extra nuisance here and there, and people largely felt like it didn't really cost anyone anything. Now it's more obviously expensive, like making the entire roadbed out of little rolling wheels that charge generators, so you have to "drive" 80mph in order to progress at 50mph...)

Re: Launch HN: Electric Air (YC W23) – Heat pump sold directly to homeowners

#500

Post by cmui »

Panino wrote: post #418
spaceguillotine wrote: post #364

How will you compete with Goodman/Daikin and needing lineset runs with usually high voltage work and panel upgrades that sometimes come with converting to a heat pump. If you don't use 24V AC controls i don't think it would take off with any installers and you seriously limit and then hinder yourself needing way more customer support. What refrigerants are you considering as there is more environmental stuff coming o…

> What refrigerants are you considering as there is more environmental stuff coming out killing 410A. I'm also interested in this. Specifically, I'm interested in R-744 (CO2) as it has a GWP (global warming potential) of only 1. R-32 (Difluoromethane) has a GWP of 675 while R-410A has a GWP of 2088. Japan has had R-744 heat pumps for years now. Drawdown lists refrigeration improvements as the single most effective me…

Some background on CO2 systems. On the one hand, great, because CO2 has a GWP of 1 as you point out. On the other, the operating pressures are much higher than other conventional refrigerants (80+bar vs 20bar). Because of this high pressure the components are more expensive, and you don't see any field installs of refrigerant lines like in a mini-split setup. Instead the CO2 systems typically come as factory sealed air-water systems.
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