Advancements in cold climate heat pump efficiency.

Brian26

Minister of Fire
Sep 20, 2013
585
Branford, CT
Yeah I agree a either one of the three would be good. I am going to be getting the low ambient temperature units. We woukd Like to be able to step away from the stove as it is our main heat source. So I think this combo will be great wood stove when it's super cold and heat pump the rest of the time. I love Bruning wood but I'd like to decrease our dependence on the wood stove
As much as I love burning wood as well I am pretty much using them practically 24/7 here. I really only burn in severe cold outbreaks. Its just so easy to set the units to 70 with zero work required. Building small fires during shoulder season sucks. Way easier to run a split that costs pennies per hour to run.
 

Brian26

Minister of Fire
Sep 20, 2013
585
Branford, CT
Yeah I do like the floor unit, just a bit less efficient. The mitsubishi units are a nice bright white they will match the white trim work, may actually just complement the living room. Im just not sure about outdoor units I guess a little landscape can do the trick. The single zones are the most efficient and have more output than the same size multi zone units
I have a floor unit and a regular wall unit downstairs. The floor console in heating mode is vastly superior to the wall unit. It can direct air in 4 directions out both the top and bottom. In heating mode I usually have it go out the bottom on the floor. A huge advantage with the floor units is they are drawing in the cold air down low along the floor. Wall units are way up high drawing in the warmest air up by the ceiling. Ideal for cooling but not heating.

I shot mine with my FLIR. You can see the nice heat it sends out along the floor.
flir_20191102T090621.jpg
 
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stoveliker

Minister of Fire
Nov 17, 2019
553
Eastern Long Island NY
I have a floor unit and a regular wall unit downstairs. The floor console in heating mode is vastly superior to the wall unit. It can direct air in 4 directions out both the top and bottom. In heating mode I usually have it go out the bottom on the floor. A huge advantage with the floor units is they are drawing in the cold air down low along the floor. Wall units are way up high drawing in the warmest air up by the ceiling. Ideal for cooling but not heating.

I shot mine with my FLIR. You can see the nice heat it sends out along the floor.
View attachment 273937
Nice pic! My wall unit (high up) can also direct up (well, parallel to the ceiling), down, and left and right.
In my case they work very well, also for heating. Obviously I don't have a comparison as I don't have a floor unit (which would have interfered with the hydronic baseboard I also have).
 

Highbeam

Minister of Fire
Dec 28, 2006
18,611
Mt. Rainier Foothills, WA
So far it seems mainly Highbeam that strongly objects to the look of the wall units. They don't bother me.
I'm coming around to the look. At some point, as with the princess stove you strongly object to, the performance benefits exceed the aesthetic drawbacks.

Myself, I've been looking at the MrCool DIY units again. The project is almost too easy with electrical being almost a bigger challenge than the actual heat pump.
 

semipro

Minister of Fire
Jan 12, 2009
3,962
SW Virginia
Myself, I've been looking at the MrCool DIY units again. The project is almost too easy with electrical being almost a bigger challenge than the actual heat pump.
We installed a Mr. Cool Universal unit in July and I'm pretty impressed so far. I need to post a review. If anyone has any specific related questions I can probably provide some insight. For instance, I discovered that while the compressor and exterior fan are variable speed the one in the air handler is not. However, it does run at a different non-variable speed depending upon whether you're running in the 2 or 3 ton mode. I was also initially unimpressed with the plastic exterior fan until I realized that the way it's shaped is one of the reasons the unit runs so quietly. I'm assuming it would be tough to get the same complex shape from a metal fan.
 

Highbeam

Minister of Fire
Dec 28, 2006
18,611
Mt. Rainier Foothills, WA
We installed a Mr. Cool Universal unit in July and I'm pretty impressed so far. I need to post a review. If anyone has any specific related questions I can probably provide some insight. For instance, I discovered that while the compressor and exterior fan are variable speed the one in the air handler is not. However, it does run at a different non-variable speed depending upon whether you're running in the 2 or 3 ton mode. I was also initially unimpressed with the plastic exterior fan until I realized that the way it's shaped is one of the reasons the unit runs so quietly. I'm assuming it would be tough to get the same complex shape from a metal fan.
The standard wall units from mr.cool MUST have their refrigerant lines poke through the wall on the right side of the unit which is a problem for me. So I became discouraged and started reading about the universal central one again.

I watched their video installing/retrofitting that unit in an old house in North Dakota and it sat there at -24 degrees making full output to keep the home above 70. Pretty impressive stuff. We barely ever get to single digits here.

I think the blower speed on a ducted unit needs to be high enough to always keep flow to all of the vents on the duct. So if it were to roll really slowly like a wall unit there might be some rooms that get no heat.

I'm honestly afraid of ductwork. I have plenty of space in the attic to run the very simple ducts to just a few central rooms but I don't know how to fab up the return air filter, and the take off on top. It seems daunting.
 

sloeffle

Minister of Fire
Mar 1, 2012
776
Central Ohio
As much as I love burning wood as well I am pretty much using them practically 24/7 here. I really only burn in severe cold outbreaks. Its just so easy to set the units to 70 with zero work required. Building small fires during shoulder season sucks. Way easier to run a split that costs pennies per hour to run.
Can you expound on how many pennies per hour you are spending to run your mini-split ? And how many BTU's you are producing ?

For example - I have a Waterfurnace 5 series ( Envision when I bought it ) and it uses 2.2kW when running on the first stage. My installation method is via ground loop so my COP is around 4.4 according to the Waterfurnace manual. At my current electric rate it costs me 35 pennies per hour to run and it produces 31k BTU's.
 

Brian26

Minister of Fire
Sep 20, 2013
585
Branford, CT
Can you expound on how many pennies per hour you are spending to run your mini-split ? And how many BTU's you are producing ?

For example - I have a Waterfurnace 5 series ( Envision when I bought it ) and it uses 2.2kW when running on the first stage. My installation method is via ground loop so my COP is around 4.4 according to the Waterfurnace manual. At my current electric rate it costs me 35 pennies per hour to run and it produces 31k BTU's.
I have net metered solar so I don't actually buy the electricity. Decent cold climate mini splits though average around 1kw per ton of output with COP's around 3.5-4. I'm in CT where electricity is expensive around .24 kwh. If I did have to buy the electricity it would cost about .60 cents/hr to run both my 12 and 18k btu units at full output. They rarely ever run anywhere near full output though. I have electricity monitors on both mine and even on the coldest days I never use more than 15 kwh's day. That's for both units combined. In the 2 winters I have had them I have never used more than 500 kwhs a month. They provide probably 98% of my heating load.

I read that air source heat pumps are pretty much on par with geothermal now. Minus the expensive ground loops. I self installed both my splits for less than $2500.
 
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EbS-P

Minister of Fire
Jan 19, 2019
535
SE North Carolina
My 3 ton heatpump is now 11 years old. Back then it was top of the line installed right before we bought the house. I just looked at the data sheet. COP47 is 3.9 at 36k and COP17 is 2.7 at 21k. All at about 2.3 kW. That’s not cold weather performance but it never gets and stays cold here. My rough math I have been using and confirmed was about on average 12 12kw hrs a day at 0.12$ kw hr. Or about 50$ a month.
This is a package unit and even today you can’t get a package unit that is more efficient. Hence why you are seeing more mini splits even here in the southern part of the US.
 

sloeffle

Minister of Fire
Mar 1, 2012
776
Central Ohio
I read that air source heat pumps are pretty much on par with geothermal now. Minus the expensive ground loops. I self installed both my splits for less than $2500.
If I was doing the same installation today I would probably choose a ASHP over geothermal due to the COP's being about the same for heating. If I was in a cooling dominated climate I think geo is still the way to go. Not unless you are heating / cooling a big house I don't think the ROI is there anymore for geo over ASHP. The two nice things about geo are, you don't have to listen to the compressor outside of the house run, and at least in my situation the cooling is dirt cheap. I spend about $5 - $10 a month ( .16kWh ) to cool my house and make hot water during the summer. :) I don't think you can do that with a conventional unit.

To give you some perspective on price, I paid 17k 10 years ago for my system. I however got a 1k back from the electric company and the government at that time had a 30% or 33% tax credit. After those two "rebates" it actually brought the prince inline with a bid I got for Trane ASHP / propane furnace. That's why I went the geo route. I got one geo quote that was as high as 26k. I would love to know the markup on a quote like that.