Heat pump mini split question

Supposedly now the better ones will heat down to 5 degrees, but I defer to the AC guys. Mad Dog

I will add that there are units that will do it, and heat the space down to around -13 or below. sizing just becomes more and more important. I usually advise those voltage range monitors from rectorseal to protect the unit from funky power especially when it is the primary heat source

Oh good.

I was starting to think I was doing a lot worse than I thought.

As long as it's properly sized I doubt there will be an issue, and for 250-300sqft I'm not even sure you could undersize it. I'm using a 12K LG minisplit in our office in NJ which is badly insulated and 300sqft and I wish I had gone with a 9K unit. At the time, the shop was so humid and people were always going in and out so I sized accordingly for the summer.

I just looked at that specific unit is only rated down to +5F for whatever reason. How cold does it get in your area and what are the chances it'll get below 5F? I can't find the unit's capacity at different temperatures either.

the spec says it runs to -4f and has ratings 5700 btu/hr at 17f, I don't see a rating at -4 but its less than 5700 btu/hr for sure. generally I only quote the low temp models for primary heating applications but I live in a colder climate. My guess is that the existing steam heat is probably still in rooms that are open to the kitchen? I think they put a design day temp around 15 for queens but I know where i'm at the design day temp gets exceeded fairly regularly so I usually size to about 10 degrees below design day

From what I saw -4F is for cooling mode only, and with a jumper moved. Heating mode is only down to +5.

in his kitchen?

Yeah you are right its not -4 heating, thats the extended cooling range, probably uses the big wind baffles to cool that low. so 5f it is. For my money I would go with a lower temp one personally

Have you done a heat load calculation? The room is pretty small, and you say R-13. Say 1000 square feet of wall (probably too big) and R-13 (probably too good, since there will be doors and windows and heat leaks). 5700 BTU would support a temperature difference of 74 degrees.

So back of the envelope fine on a 17 degree day, but the heat output will drop and the heat load increase on a 5 degree day.

A kitchen will be a lot more tolerant of a little bit cooler temp than a living room or bedroom or bathroom on the coldest day. That being said, my kitchen was always cold until i replaced the cabinets and found that in about 1950 they cut a hole in the drywall to install a vent when they hooked it up tp the municipal sewer then just covered up the hole with a cabinet.

then they got what they paid for!

now use the tax credit towards the problems!

Mitsubishi has been around a while and I imagine they have parts for at least the extended warranty period the same as the other big brands. I can get some really old LG split parts for units that are out of warranty even. Around here most are ready to upgrade after a decade or so because they are getting additional rebates for a new install, and a new warranty.

I expect better from you Matt.

But, even if it was R290, It's a small charge.

yes Daikin is probably the biggest real name brand at this point, between them mitsubishi LG and fujitsu parts seem to be available. Midea I think produces far more units but they are notorious for stopping parts support very quickly the initial cost reflects that as they are usually inexpensive. Not to say everything Midea makes is junk, much of it performs its task reasonably but they aren't made to be a 15+ year appliance typically.

I must be really losing my edge these last few weeks because I thought it was a mitsubishi lol, between that and reading the spec sheet wrong I think I'm burned out, luckily a short vacation is coming up.

I would be very concerned about that lineset. The mini split linesets with the white insulation are notorious for leaks due to formicary corrosion. This happens when moisture gets in between the copper and insulation due to the ends not being sealed properly.

I've encountered this several times myself and heard numerous horror stories about it. You get leaks in the middle of the lineset that are a pain to find.

It's recommended that the ends of the insulation get tightly zip tied to prevent moisture from getting in. Foam insulation tape can be used to cover the ends and wrap any bare copper tubing.

Fujitsi are popular too. Mad Dog