My 4-ton will keep the house at 68F at 17F outdoor, and still cycle. But my house is insulated and air sealed very well. It seems unlikely that if your unit can't put out enough heat at 27F to keep your house at the setpoint, that even a low-temp heatpump would do at at 0F.
Cold Climate Heat Pumps
- Thread starter Snagglefoot
- Start date
My 4-ton will keep the house at 68F at 17F outdoor, and still cycle. But my house is insulated and air sealed very well. It seems unlikely that if your unit can't put out enough heat at 27F to keep your house at the setpoint, that even a low-temp heatpump would do at at 0F.
Nope. You need to see the output of these new pumps. 54,000 BTU per hour at 5 deg F is not a problem. You never mentioned how many square ft your house is and how many square ft of windows you have.
My house is 3300 square feet not including the basement, which itself is another 1500 square feet. I couldn't tell you how many square feet of windows I have, but they meet 2017 energy codes for Virginia.
At 5F outdoor this unit still kept the house at 60F, although it was running continuously to do so. (I run with aux heat disabled).
What size heatpump outputs 54,000BTU at 5 degrees F?
I don’t mean to be combative, but try www.arcticheatpumps.com It’s mentioned in posting #2. I have to leave for a while.
Let me re-phrase the question. Would a unit capable of putting out 56,000BTU at 5F be capable of modulating down enough in cooling mode to avoid short-cycling given that you're currently running a 42,000BTU unit? Or do you not use it in cooling mode?
If you do use it in cooling mode, is your heat load enough to keep that 42,000BTU unit from short-cycling? I'm running 48,000BTU unit and I'm well south of you.
The temps here are in the 90’s and the AC runs every afternoon, into the evening. Fortunately it finally cools off during the night with the mountain air.
I have no data on how these low temp heat pumps do in the cooling mode.
Wow. It gets well into the 90s here, but my house takes 12 hours to gain 10F. So what I do during the summer is have the AC drop the temp down to 70F around 3am, the daily low. It usually takes till almost 6pm to reach 78F. I have it start dropping the temp down to 75F around 10pm. So basically my air conditioner does NOT run at all when the sun is up. It doesn't need to. I have only a couple of east and west-facing windows, and about an acre of trees to the south. My house is oriented perfectly for energy efficiency.
Sounds like its low on charge or the indoor fan speed is too high. Should be putting out a lot warmer air than 77 degrees with an outside temp of 43.
A true communicating system would be able to match capacity at any temp. But like any other system they need to be sized right from the start.
Thanks for bringing this to my attention. Turns out is was a measurement problem. I was using a laser guided infrared temperature gun aimed at the outlet in the floor. It was aimed at the inside of the duct which is shiny metal. I then put a contact type temperature reader on the duct and it read 40 C, or 104 F. Infrared readers don’t work well on shiny materials.
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Here’s a question I could not not find the answer to on the net. At what outside temperature is a 60,000 BTU per hour ( 5 ton) unit rated at. We all know about COP’s but what’s the assumption on the outside temp for the nameplate output?
Probably every unit is different.
https://hvacdirect.com/5-ton-14-9-s...-air-conditioner-split-system-id128208-1.html
This one is 5ton and for the cooling can also cycle down to 12k-36k
checking to see if it lists other temps.
Edit: checked all 5 manuals that come with it and it just mentions temp ranges it will operate in.
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Gosh, the summertime ratings are not very good. EER 11.3/EER2 10.5? That would burn a hole in my wallet in Central Texas.
Going from memory it's something around 42F. Find the performance data for the unit. Goodman performance data is easy to find. Some other manufacturers hide it behind a login..
You can optimize for one over the other (heating vs cooling)
This is the ARCTIC series for use mostly as heat pump in cold areas.
I'm guessing that it's modulating down so much in cooling mode that it's killing the performance. There's no secret as to how these units achieve their heating mode performance--they are oversized units.
Back to my original - Last night it was 30F here . I didn't turn the upstairs HWBB on yet. Bosch T-stat was reading 64F which was the set point on heat. It would turn on and off randomly. Downstairs HWBB T-stat set on 65F. According to my IR temperature gun I was getting 84-87F out of the registers so about a 20F rise in temperature. I'm not sure how that would perform overall at that 4F rating.
Helped to try and diagnose wife's friends heat pump setup. They were only getting about 68 degrees from vents and it was 45F outside. They had it "charged " over the summer as AC wasn't working. I don't have the equipment or certifications etc for freon or deeper stuff. They called another HVAC guy that came by after work. He checked and said Schrader valve is leaking and not sure if other. He said he'd be back Monday/Tuesday when it's warmer out to evacuate/change valve/recharge/check for other leaks and get correct pressures. He also went through the system to find previous owner had stuff wired wrong so his Electric heating coils were not working. He got that corrected so they had heat at least. So far they paid $250 which is actually really good as he was there almost 4 hours.
It also doesn't meet the requirements for air conditioning energy efficiency anywhere in the USA (14 SEER northern, 15 SEER southern).
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My gas furnace has yet to fire, which is wonderful, I'm using a lot less natural gas and the heat pump is keeping the house where it should be. Since my unit is 2.5 ton, it will simply not have the capacity to adequately heat the house at some point below around -10C I suspect, maybe -15C? I'll probably start playing around with it when the weather gets colder.
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How big of a space are you trying to heat? Is yours a traditional heat pump or inverter communicating system?
