Heating and cooling for a small space
user-7643731
| Posted in Mechanicals on
Hi folks
I’m looking for ideas for heating and cooling for a standalone small (150 square foot) outbuilding that will serve as a home office. This in in western oregon (zone 4c). The space will be well insulated (r30 wall and r60 ceiling) and reasonably air sealed. I am looking for something I can install myself and would be sized for a small space. I have started by looking at minisplits and point terminal heat pumps and am curious about their relative merits as well as any other options.
Thanks,
Chris
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Replies
A small minisplit is perfect for this. You won't beat the small size, and you'll have both heating AND cooling this way. I wouldn't even consider anything else here. If it was only a shed, I'd maybe use a small unit heater, but for an occupied space like an office, a minisplit is absolutely the way to go.
Bill
In warmish climate, you can get a window mount inverter heat pump such as this:
https://www.midea.com/us/Heating_Cooling/window-air-conditioners/12000BTU-SmartInverter-AirConditionerWindowUnit-MAW12HV1CWT
These are signficiatnly quieter than your typical window unit and also much more efficient.
I would mount it in a sleeve instead of a window, try not to put it in a middle of a wall as it can cause resonance and noise issues. You can add a plug in heater as backup for those cold snaps.
That's interesting to me because I have a similar need. But two red flags: first, it only heats down to 41F, which is not really when heat is most needed. Second, it doesn't seem possible to buy the unit. I clicked on the "where to buy" link. Online it lists Amazon, but it's out of stock. Clicking on "buy offline" tells me that it's not available to buy in my area. Home Depot also has it listed but also out of stock with no way to special order.
user 731,
Akos's suggested unit is quite the bargain, but do be aware that it is rated to carry over three times the area you are proposing. It may be that short cycling is not as be as big an issue with an inverter unit though the capacity to dehumidify the air may fall if chronically short cycling. The splash page says "powerful heating and cooling" between 40 and 110F, a range that favors most of the CZ4C. With shifting weather patterns causing havoc, you may find that your winters no longer range below freezing. A backup heater would probably be just fine given your proposed insulation levels.
If you are not planning on excessive glass to go along with your high levels of insulation, you may find a read of the following thread instructive. The OP lives near Minneapolis and faces a far higher range of temperatures to deal with. You may find what I suggested to be of potential value to your similarly sized office.
https://www.greenbuildingadvisor.com/question/thermaray-electric-radiant-ceiling-heating-system
I did a quick google of "AC with heat" and one unit by LG caught my eye because the specs seem to infer that heat is supplied by resistance not a heat pump. (7600BTU LG LW8023HRSM at Amazon and big box stores) This way of heating may be a work around that favors the LG over the Midea. Though still over sized and less efficient on the whole, I suspect it will supply heat down to whatever few days fall below 40F. You may find that your office equipment may provide more heat than you think if using desktop computers over laptops, so be sure to think through your gains and losses carefully.
I also stumbled across this unit (link below). Not too much info on cost or temperature range when heating, but maybe worth a look. Still big.
https://www.gradientcomfort.com/products/gradient-window-heat-pump
It just drives me crazy that air conditioner (and dehumidifier) manufacturers are allowed to size their units by "square feet." It would probably be just as useful to size them by the weight of the building, although that might get confusing when deciphering whether a five-ton heat pump refers to the cooling capacity or the weight of the building.