Which heat pump for radiant heat other than Arctic?
I asked questions earlier about HVAC design here:
https://www.greenbuildingadvisor.com/question/please-help-me-understand-my-mechanical-plan
Mechanical engineer was asked to revise, and returned with the revised heating load of 58MBH.
I asked to avoid using natural gas (which was originally only planned for a combo heater providing domestic hot water and hot water for in floor hydronic heat).
Current proposal – resistant heating for domestic hot water heat, and air to water heat pump for the radiant infloor hot water.
My question relates to the heat pump for the in-floor heat.
With 58MBH heating load, the engineer suggests this unit:
https://www.arcticheatpumps.com/arctic-heat-pump-060a.html
Which seems monstrously large (specs below).
https://www.arcticheatpumps.com/specifications.html
Is there a better heat pump option out there to supply hot water for infloor hydronic heat? I would love something QUIET, small, efficient. It cannot be electric (because of local SB-12 rule and CI values I cannot meet). I am in Zone 5A.
Please note domestic hot water can be heat pump or not – it is currently planned as electric heater because of the noise that heat pumps have.
But I will have air to air heat pump installed to supply cool air in the summer, which would also provide heating backup when and if the temperature drops low so that the heat pump output for hydronic heat does not fully meet the needs.
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Replies
Look at Chiltrix, Taco System M, SpacePak. Also LG Hydro.
If you're going with air-to-water, you might find it makes more sense to put in hydronic air handlers for heating and cooling than to have a separate air-to-air for cooling.
I would check out SpacePak line of heat pumps. You will need to do a block load heating and cooling calculation to size the unit. I am in Zone 6A and the block load is 36K BTUh for my house design.
Thank you - Solstice 060 looks better (quieter, split rather than mono). On paper, I prefer it.
There are a couple of options here.
Instead of AC only, you can spec a heat pump. This heat pump can be either sized for the full load of the building or it can be sized to make up for the shortfall of a smaller air to water unit. In either case you'll satisfy sb12 without needing extra insulation.
If you do size the heat pump for the full load of the building you can install a resistance boiler for the floor heat and still meet sb12. As long as the heat pump is providing the bulk of the space heat, the operating cost on this setup is not much higher than an all heat pump solution and much cheaper install cost. In this case you do have to watch your floor temperature, it should only be set a couple of degrees above room setpoint. Areas such as bathrooms or kitchen can be cranked up a bit as they should not be large percentage of your floor area.
If you are looking for an all AWHP solution, all 5 ton units will be big. There is no way around that.
BC has a decent list of all the AWHP available in Canada:
https://www.betterhomesbc.ca/wp-content/uploads/2022/10/Air-to-Water-Eligibility-List-Oct-2022.pdf
Akos - thank you
Yes, it is precisely because of SB-12. I was told that having floor heat on resistance heating would require another inch of CI which current design cannot accommodate.
But I spotted this exception:
" (17) Except as provided in Sentence (18), a building is permitted to be designed in conformance with any of the compliance packages available for the climate zone that the building is located in, if the primary space heating of the building is supplied by (a) a wood burning appliance, (b) an earth energy system, or (c) an air or water source heat pump that does not use electric resistance as a back-up heat source. "
and I was told that using resistance hydronic in floor heating would not qualify me for (c) exception.
Thank you for the link to BC - I found Spacepak SIS-060 units (split) which seems a little quieter than the proposed Arctic but more to the point do not require glycol (because it is not monobloc but a split). I find the whole idea of hydronic glycol mix off putting.
https://www.literature.mestek.com/dms/SpacePak/SD-SIS-1022.pdf
If the heat pump is sized for full load, it is the only thing that needs to be on the drawings. Provided the heat pump does not have a backup strip heater it will meet sb12.
I have a permit with hydronic heat on it. I suppose we can still make an argument tha t is is not a backup?
Figure out what you want and get the permit revised.
The reality is that HVAC install costs are pretty much detached from equipment costs. I'm pretty sure your lowest cost option is a modcon even though an AWHP is about the same cost. This is mostly because the installer knows how to install it and are fewer unknowns. If you add a lot of new ideas and equipment into the mix, install costs quickly get out of control at which point any operating cost savings is never.
Since your permits are already in, the cost of updating the drawings and new approvals, I don't think a change is the best way to go.
About the only thing that is worth looking at is the LG Multi V with a hydro kit that is also has ducted units connected which can do your cooling. Because this unit has a HSPF rating and it is an air source heat pump, it will qualify for the full energy rebates. It also means only one outdoor unit.
The only issue is finding an installer that is qualified for installing it as this is a semi commercial unit.
Actually, I love the collective mind - thank you! Forget SB-12., forget Arctic.
How WOULD you heat the water for hydronic heat - assuming I only have 200 Amps service? I thought heat pump for cooling (and backup heating), radiant heat and domestic hot water electric?
Or would Sanco2 unit (or something cheaper?) heat pump make sense for domestic hot water (it does look quiet... but expensive?)? I mainly want electric water heater (for hydronic and domestic) because I do not like noise that heat pumps make and have no room to distance the heat pump exterior unit from the house (urban lot). Tiny mechanical room too (8 by 10-ish).
I am trying to avoid connecting natural gas, but I may be cutting close to 200Amp load overall (with ERV, all-electric stove/washer/dryer).
I can tell you what I did in my house.
Chiltrix heat pump for both heating and cooling. Radiant floors in the bathrooms, radiant ceilings in the main rooms. A hydronic air handler on every floor for cooling and to supplement the radiant heat. (See https://www.chiltrix.com/documents/FCU-fan-coils.pdf) A heat pump water heater.
The heat pump water heaters have gotten a lot better noise-wise and will probably get even better.
The Chiltrix heat pump has an option to provide domestic hot water, but I didn't go with it. It just seemed more complicated and expensive than having a HPWH in the house. But if noise is an overriding concern I'd look into that.
If I were to do it today I'd take a long look at the Taco System M. It's one of the first heat pumps to be sold through a major player. It's a rebranding of a German model that has a successful track record.
Not to get too side tracked, but talking about a German heat pump... Germany is enroute to ban natural gas/oil installations as soon as 2024. In addition, they will be quickly requiring current gas/oil heat to be replaced for all except homeowners over 80 and people on social welfare. Most houses in Germany are heated with radiators or other hydronic systems. I'd expect we are about to see a huge amount of A2WHPs coming out. And I bet very plug and play type systems since they have a huge shortage of HVAC workers in Germany to top it off.
One of the advantages of air-to-water is it doesn't take an HVAC tech to install it, the refrigerant is in a sealed system and it's just a matter of making water connections, usually PEX.