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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

#601

Post by telcal »

roamerz wrote: post #75

How do you compete with the likes of Mr Cool? Me and my father replaced his 15yr old heat pump/air handler in his house a few months ago. Took us a weekend and about $4500. That was a 3 ton unit. Similarly we installed a 1.8 ton split unit in a new house. About $2500 for that one. Both were complete kits including thermostat and required no refrigerant install as everything was pre charged. The 3 ton was even 21 seer…

We also installed a Mr Cool DIY system in our house about 3 years ago. We also did it ourselves. It works well, no complaints, and has an app that you can control it anywhere with. 36k BTU 21.5 SEER Multi-Zone all for about $3700.

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

#603

Post by nkurz »

throitallaway wrote: post #188
cosmosisjones wrote: post #85

Earlier quoted context omitted.

so what about places like Duluth, MN where it can be -20F ambient, then -40F to -50F with a windchill for several weeks of the year?

Windchill is irrelevant here, it only indicates what the temperature feels like to warm blooded mammals.

I was tempted to give a similar answer, but I'm not so sure it's irrelevant. Yes, the windchill won't affect the energy efficiency of the heatpump. But it will affect the rate at which the house loses heat, and thus the BTU's the system needs to provide to maintain a temperature. If the heatpump has been exactly sized to maintain a house temperature of (say) 70F at the expected winter low, adding a strong wind on the exterior of the house seems like it might make for a chilly morning. The effect isn't as strong as it is for bare skin at body temp, and hence the exact numbers will be off, but it's still there, right?

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

#604

Post by ta1243 »

divbzero wrote: post #576
cmui wrote: post #564

Earlier quoted context omitted.

Mind sharing some details of your install - equipment model/size, controls, and cost of install?

Is there a straightforward way to estimate whether a small (24 kbtu), medium (36 kbtu), or large (48 kbtu) unit would be most appropriate for a given home?

For reference for international users, 24 kbtu is 7kW, 36 is 10kW and 48 is 14kW

I'm not a heatpump export, but if that's continuous output, with an SCOP of say 3.8 (what I had quoted in the UK for an airsource -> water -- UK heating is typically hot water run from a boiler through radiators in each room rather than pumping hot (or cool) air direct to the romm via ducted which seems common in the US, perhaps because of the historical desire/need for aircon)

That would require 1.8/2.6/3.7kW of electricity to run. In the UK at 35p/kWh that would mean 91p to generate 10kWh of heat. For reference my oil boiler at 95% efficency and current prices is about 6p/kWh, but we have had insanely high electricity charges this year. Back in September my oil heating approached 10p/kWh -- about £1 a litre.

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

#605

Post by hedora »

PaulDavisThe1st wrote: post #527
hedora wrote: post #450

Earlier quoted context omitted.

Even in coastal California, most ducted heat pumps have a built in electric or gas furnace. I imagine anything sold in areas where it actually gets cold will as well.

Here at 7000' near Santa Fe, I know dozens of homes, many new construction, that are heat pump only to all effects and purposes (i.e. they may also have fireplaces but these are not part of the normal heating systems nor part of any plan for the 0F-5F winter nights we can get. Heat pumps can handle things by themselves down to around -10F to -15F, if correctly sized and installed.

What brand?

Most of the low temperature ones I’ve seen include resistive heating. At some point the COP of the heat pump approaches 1.

Also, having heat to -15, then switching to no heat isn’t ideal.

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

#606

Post by bluGill »

saenns wrote: post #588
cmui wrote: post #564

Earlier quoted context omitted.

Mind sharing some details of your install - equipment model/size, controls, and cost of install?

I'm looking at this 36,000 BTU/h unit for $3,750. Pre-charged line sets make it accessible to homeowners https://www.amazon.com/dp/B08FGLMZB8?_encoding=UTF8&aaxitk=e...

Often you can get EPA certification and all the tools for less. But that system does get good reviews.

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

#608

Post by simplyaccont »

briHass wrote: post #542
simplyaccont wrote: post #359

Earlier quoted context omitted.

there are diy systems with threaded connectors, pre-vacuumed units and linesets filled with refrigerants.

True, but those linesets introduce other downsides. They can't be cut to length, so you often have to have unsightly loops of extra line set somewhere, and the loops can potentially trap the oils that mix with the refrigerant to lubricate the compressor. They're also much more expensive, and anecdotally, I've heard of leaks from over/under tightening the threaded connections. Not to mention, installing them without a…

>True, but those linesets introduce other downsides. They can't be cut to length, so you often have to have unsightly loops of extra line set somewhere, and the loops can potentially trap the oils that mix with the refrigerant to lubricate the compressor.

well, i run my through crawlspace. had only a small extra loop. in crawlspace.

>They're also much more expensive,

per unit - yes. but... if you doing to diy mini-split not with precharged lineste, you need vacuum, refrigerant and probably license to buy it. it raises cost and make it viable if you plant to install multiple units (have coworkers that did it). if you want to get it professionally install, than in addition to ~$1.4k for 2ton unit you look into $6k-$8k for labor. Those were prices year ago for install in garage with 240v line connected to 40amp breaker available at install location.

>Not to mention, installing them without an EPA 608 certification is technically illegal.

technically, i guess much of the work done by home owners must be done by certified professionals and get approvals and inspections.

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

#609

Post by c_o_n_v_e_x »

antisthenes wrote: post #379
dmarlow wrote: post #306

Earlier quoted context omitted.

Same thought as well. I recently self installed an 18k BTU unit. The lines came pre-charged, but I wanted it to be run exactly to length. For someone to come and do just that part (cut, flare and vacuum/charge the lines) cost me just $150. I got the unit (a pioneer) for under $900. The rest of the world has heat pumps figured out, no need for a tesla-ish version charging a premium. Cost will be the biggest factor for…

> The rest of the world has heat pumps figured out, no need for a tesla-ish version charging a premium. USA has heat pumps (the technology) figured out as well. What the USA does NOT have figured out is how to accomplish trades like HVAC and construction without massive grift.

>What the USA does NOT have figured out is how to accomplish trades like HVAC and construction without massive grift.

The US has professional licensing schemes which increase costs. I had to work 5 years in the field doing HVAC work before even being eligible to get a license. Licensing limits the supply of labor while (in theory) establishing better quality. I've lived in countries with zero professional licensing and the quality of work is atrocious.

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

#610

Post by phasetransition »

amluto wrote: post #431
phasetransition wrote: post #382

Earlier quoted context omitted.

Upvoted, BACnet already exists as an ISO standard: https://www.iso.org/standard/37298.html https://bacnetinternational.org/ The example application in the Ethernet Alliance one-pager on single pair Ethernet is HVAC: https://ethernetalliance.org/wp-content/uploads/2020/10/EA_T...

FWIW, if this were my startup, I would probably use 10BASE-T1L. The programming model is simple, and cloud or other “smart” integration is natural if the system already uses IP. For that matter, one ought to be able to support wired 10BASE-T1L and wireless Matter/Thread thermostats without much duplicate effort. This could be prototyped on a BeaglePlay :)

FWIW,

BACnet allows multiple PHY implementations, including 802.3

I suspect that 802.3.cg is also kosher, but haven't looked in detail. It's been 5 years since I looked seriously at whether BACnet was the correct solution for a product family.

Single pair Ethernet is indeed cool tech.

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