Heat Pumps - Why they are already a wise investment

[henene4]

I subbed to him years ago and he once again made a great video.



If you don't want to watch the entire 35min thing, I'd recommend the last 5 minutes.

He does a very informative calculation:

Considering ALL loses (generation, transportation), natural gas as electricity source brings about 40% of its energy to your home.

Burning it at home gives you upwards of 90%, but never actually 100%.

If you however compare the roundtrip efficiency during heating, a heat pump only needs a COP of 2.5 to get 100% heat captured.

Simply because a heat pump moves energy so efficiently that even if it isn't a particularly efficient unit, it (usually) more then offsets any electricity generation and transmission losses.

And in cases where it doesn't you can switch back to your main heat source.

That switchover happens automatically and is optimised towards efficiency.
So a no fuzz solution that is always as efficient as possible.

A fun side note:

The EU has heat pump tumble dryers as the de facto standard by now for home use at least.

These are not the best thing in terms of efficiency, but even their systems usually reach a COP of at least 3.5.

Our conventional dryers use about 2kW give or take as heating power.

Our HP dryers have compressors around 500-600W.

So, a 2kW inverter heat pump used in a US clothes dryer could probably dry in the same time as normal electric dryer, yet still use half the energy.

 

[wayupnorth]

Heat Pumps are and not your best depending where you are. In the colder weather we get here you use alot more electric resistance heating but you have a whole house A/C in the real warm weather. Friends of mine put an expensive geo-thermal system in when they built their house and they are very comfortable and much happier with the lower energy bills.

 

[DADoES]

 
RJ had a geothermal system installed in March 2009.  I don't think he runs it enough to ever get a payback vs. a non-geothermal system.  He stands rooted in front of his propane fireplace during cold weather.  Has been at least two repairs.  Circulation pump was one IIRC.

 

[askolover]

I hate heat pumps. My last apt had one. Growing up with gas heat I froze all the time. MIL has one now...she hates it too. You will never convince me that it is cheaper to just run an air conditioner in reverse...especially in an area that has gas service.

 

[warmsecondrinse]

#3

My understanding is that they are more efficient than gas down to a particular temp that's determined by the unit and the heating demands. As the temp drops electric resistance heat is phased in bit by bit as needed. However, there does come a temp at which is is more efficient to use the electric or other backup.

Last I looked into it, which was prob 20 years ago, heat pumps were more efficient down to 35-40F. I think a few members have much newer units that work down to 20F or so before it's cheaper/more efficient to run other kinds of heat.

 

[DADoES]

 
<blockquote>As the temp drops electric resistance heat is phased in bit by bit as needed.</blockquote> Depends on the design and capability of the system.  Newer and/or higher-end systems have two or more sets of individually-staged heat strips.  Lower-end units such as mine may have more than one set of elements but run them all or none.  I can turn off one of the breakers and have only one set able to run but the system can't do that automatically.

 

[circlew]

Some of the newer systems use inverter technology, like is used in mini-split units. They can supply an air handler or individual fan-coil units. There are also air to water heat pumps that can supply hot water to radiant floors, convectors, radiators, fan coils, or air handlers. Nordic, a company in Canada, makes units especially suited to extreme cold weather.

 

[yogitunes]

I guess it depends on the area, and system used....

but have run into more people this season who have these units...and not one is happy with them...

barely enough heat, and cost of repair/maintenance is more than the energy savings...

cannot say its a system I would want....

 

[tolivac]

When I lived in Manassas,VA for several years lived in a townhome that had a Trane HVAC system.Heat pump-electric heater in winter-AC summer.Worked REALLY well.During two big snows-2Ft first one,1Ft second.Simply shoveled the snow away from the condensor unit-worked great held well only needed backup heat just a few times.The efficiency of these heat pumps depend on both refrigerant and compressor efficiency.Efficient refrigerants can funcion in below freezing temps well.If not then the system has to use the backup heat.

 

[ozzie908]

Have a reasonably low priced

HVAC its only works in one room but will drop the temp in the whole house when its hot and I have used it a couple of times to warm me instead of the electric fire it will heat the room very quickly with the doors closed but we have a very good hot water/radiator system that heats the whole house, If I had realised how good these new systems are I would not have updated the central heating but would have had 3 heat pumps put in as that would have been less than the new boiler.... Live and learn.

Austin

 

[appnut]

There is no natural gas on my street. Houses are all electric and range in age being built from 1972 to 1984. Mine was one of the last two built. The HVAC was a RUUD heat pump, albeit builder's grade. It was one of the reasons why I bought my home. I was familiar with heat pumps. Friends that used to live behind us in our old house were responsible for us moving to the new house September 1961. Their house was a gold medallian all-electric house and had a heat pump. The most recent artic blast was the 2nd coldest I've experienced since living in this house since January 1986. The lowest it got was 2 degrees F. The coldest was a couple of days before Christmas 1989 and it got down to -4 degrees F. The RUUD heat pump couldn't keep up and could only heat the house to 64 degrees with the emergency heat setting. My current Trane XL20i kept the house at 69 degrees despite all the snow & I that was around it. I couldn't get near it because of all the snow & ice to clear that from around the unit. I got my bill last Friday, 1806 kwh for the billing period. In the past two years, my highest consumption was 1550 kwh in June 2019 or July 2020. So I was pleased.

 

[petek]

When I replaced out mini split last September I went with a heat pump model as it was only a negligible cost increase. I figured if for some reason our boiler went down I'd have some sort of heat until it was fixed. I was a bit too nervous to even turn it on these past few weeks of minus weather thinking that with my bad luck of late with appliances it would probably break in that cold and I'd have another big kerfuffle to deal with. I did turn it on last for a few minutes because it was just above freezing, and it did pump out a lot of heat.

 

[norgeway]

If you live in

Florida or somewhere warm, they are ok i guess, I wouldnt have one personally, old cold air blowing, I grew up with oil heat and i like hot air

 

[sfh074]

Just had ....

a SEER 18 heat pump installed at my mom's condo, a Carrier unit. The outside condenser unit comes up to my chest and I'm 5'11". The thing looks huuuuuge.

But anyways, yeah ...... still the usual blast of cold air every time it starts blowing and when the outside temp is below about 34, the damn thing runs what seems forever before it cuts off. As for the inside temp, it does do a fairly good job at maintaining the 74 degrees mom keeps it set at in the winter. Her power bill is a bit lower compared to the older unit by about $20 a month. At that rate it'll take 200 winter power bills to recoup the cost. LOL Curious to see what the average AC bill will be.

 

[bradfordwhite]

Heat pumps NOT a good product.

Mini-Split AC ONLY units are a very good product however.

Baseboard heaters and EXCELLENT insulation is the best way to heat.
We've lived and experimented long enough now to know that insulation is key to keeping our environments comfy whether heating or cooling.

Baseboards make no noise, have no moving parts, are cheap to install, have 100% efficiency, can be controlled per each room, They don't explode or kill occupants silently, there are no dirty ducts to worry about, oh and again Q-U-I-E-T.

And quiet is the reason to choose a mini-split. Preferably a 120 volt model that way if you have a solar system you can use a standard 120 volt inverter to power it.

I used mini split heat pump last year. I knew as a heat source it wouldn't work because heat needs to be coming from floor level. A mini split is hung up high on a wall which means you'd have to blow the heat down. So there's the draft.
Then there is the unnecessary noise. I HATE mechanical noise. Our world is polluted enough already with idiots making noise.

I also owned a home in the Chicago area that had been made "all electric" in the 70s with a heat pump.
Terrible.
That fan had run so long on the air handler it was vibrating terribly.
When it came on there was the cold draft.
Then MORE noise from TWO units running.

That thing got ripped out and put in a standard gas furnace and AC unit. This was 2003.

I will never install anything with duct work again either. All that dust you don't have access to plus it's difficult to zone rooms. Then there is the cutting of the structure to install them.
The noise that vibrates from room to room. No.

----

Mini splits can be bought and self installed with the pre-charged lines.
There are vids on YouTube showing how to do it.

This one is 12,000 BTU. Depending on your insulation that can do quite a bit of space.

 

[henene4]

Dunno what you are talking about noise wise.

If your house is that well insulated the outside noise shouldn't come in.
Any thermal insulation is usually good noise insulation.

And inside units I've yet to find anything over 30db.
That's quieter than most fridges.

Efficiency of 100% is nice.
But having effectively 300% or more is better I'd say.

Even a full house system can technically be run from solar.
Just depends on the setup.

Especially if you are arguing for electric baseboard heating.
If you can heat a whole house with those on solar, so can a heat pump.

And the draft thing is somewhat confusing to me.
If you already have AC apparently that isn't much an issue unless you choose to.

That generally also confused me:
If you have forced air heating these systems shouldn't be much different?

Yes, if your system doesn't have the delay before running the fan (waiting for the coils to heat up) the cold air blast might be an issue.
But otherwise heat should be similar, maybe not as intense.

I do like my heated floors and radiators, sure.

But most seem to forget that there are a lot of different heat pump setups.

A heat pump just names the compressor based nature of the system.
Where it pulls the heat from and where it dumps it to is a whole different story.

The most common systems over here are air-water-heatpumps with underfloor heating.

The heat pumps are usually sized 1/3 to 1/4 of what would have been installed for oil or gas.
Our house has a 20kW oil system currently that is almost a little oversized. We use something like 2000l of oil a year I think.
So we'd be using a 5-8kW heat pump.

Depending on location and model you choose you either have a split system or like one of my cousins everything is situated inside in your utility room and only an air duct connects outside.

The heat exchanger pulls the heat from the air and puts it into either your hot water storage or your heating loop.

Main downside is that hot water temperatures are kept relatively low (about 50C).
Depending on system that necessitates a periodic automatic heating above 70C for water safety that uses a resistive heat source.

But for heating it really doesn't change much.
Our heating loop runs at about 48C at 0C outside.

Biggest advantage in my view is that for many, it just straight is a drop in replacement.

Technology has advanced so far that 90% of homes over here can be heated that way without major modification.

No more expensive deep well drilling for geothermal heat pumps like we would have needed 10 years ago.

And in the US any house having central AC could cover at least a certain amount of their heating pretty environmentally friendly.

Sure there will be good and bad implementations.

Biggest issue appears to be that cold air blast issue several mentioned.
But again - the unit in the video already solved that with a pretty simple timed or temperature guided delay on when to activate the fan.

 

[henene4]

Noise and price

So I actually just checked out of curiosity.

In the EU, noise levels are limited by law (of course they are).
Outside units are not allowed to be louder than 35db at 3m distance during night time.
35db is a decently quiet fridge.

A air-water-heatpump suitable to heat our entire house plus warm water would run around 15-20k max plus installation.

Our oil system was 15k including a new warm water tank and installation IIRC about 8 years ago or so.

However the heat pump would currently get a 50% rebate given it replaces an oil system.
So while running it might not necessarily be cheaper, it would just be cheaper to get it.

 

[volsboy1]

Ours Kicked ass up at the farm when it got down to the single digits .
I grossly oversized it the Mitsubishi Hyper heat,but when you have a inverter compressor that is less of a problem..
I turned off the 2 American standard split heat pumps and just left the fans on and set the temp at 73 on the Mitsubishi just to see if it would have any issues.
Its a 48k unit with 4 indoor units . I have two down stairs and one in the middle and one on the very top floor.
The unit did not even struggle the air coming out is HOT HOT .
My Dad is going to rip out the Trane And American Stand heat pump units and go
with Mr Cool brand. Those units are 14 years old, We have had a great service from MR cool and sense the Trane Handlers are new as is the coil that Mini Split will work. They heat down to -22F . Trane used to be the best not anymore. I have seen 4 new Trane Heat Pumps in a new tract of Homes and the Tranes are all using L.G. compressors. They could of went with Copeland compressors. I would have went with Panasonic or Toshiba Scrolls before I touched L.G.

 

[gizmo]

net metering

We are off-grid so it doesn't apply to us, but in my State (Victoria) we used to have net metering for homes with the old "moving disc" meters, but now all grid-connected homes in the state have smart meters that calculate energy in/ energy out separately.

For an initial phase-in period the power companies had to pay a legislated 60c per KWH. Retail cost of power is about 30c. Obviously a strong incentive to put solar on your home. The mandated rate dropped to 45c then went unregulated and fell to about 6 to 8 cents, now is up to 11 or 12 cents per kwh for your exports to grid. Some lucky folks signed LONG contracts at 45cents and will still be getting that for another couple of years.