Heat Pump Water Heater?

[diesel44]

Looking to take advantage of the Greener Homes Grant/Loan. Since my current hot water tank is past its prime, I am looking to change it. The grant/loan covers HPWH's only. Is this a good idea in Calgary. I will be changing my hot water tank anyway and 0% loan is nice to upgrade from standard tank.

What do the plumbers of A.O. think?

[CaberTosser]

I’ve seen the concept applied commercially, but would need to see how the #’s work out in terms of utility costs in our area. The thing is, electricity is going to be going nowhere but up as the grid gets strained with electric vehicles, I think Nat Gas will be less volatile as utility costs go, even though it’s been through a wild ride recently.

When they break, you’ll need an hvac tech to fix them if it’s anything wrong in the refrigeration circuit, as plumbers don’t carry vacuum pumps or refrigerant gas for changing compressors.

I’ve always thought it would be neat to have a system where the heat from your A/C, fridge or freezer got scavenged into your domestic hot water. I’ve seen such a system at Costco where their significant refrigeration can shed heat into the domestic hot water system through heat exchanger tanks that are piped upstream of the water heaters, serving as a preheat for the domestic hot water.

[Jamie Black R/T]

Originally Posted by CaberTosser

I’ve seen the concept applied commercially, but would need to see how the #’s work out in terms of utility costs in our area. The thing is, electricity is going to be going nowhere but up as the grid gets strained with electric vehicles, I think Nat Gas will be less volatile as utility costs go, even though it’s been through a wild ride recently.

When they break, you’ll need an hvac tech to fix them if it’s anything wrong in the refrigeration circuit, as plumbers don’t carry vacuum pumps or refrigerant gas for changing compressors.

I’ve always thought it would be neat to have a system where the heat from your A/C, fridge or freezer got scavenged into your domestic hot water. I’ve seen such a system at Costco where their significant refrigeration can shed heat into the domestic hot water system through heat exchanger tanks that are piped upstream of the water heaters, serving as a preheat for the domestic hot water.

I could be wrong by I think the OP is referring to a on demand water heater. Not actually a heat pump.

[jef612]

As usual - Caber is spot on.
I have been in a couple of rooms where I have been told that the HPWH are coming and will be the new norm - but honestly if you can hold out I would wait.

There is a significant cost difference obviously. And if your electrical grid is fossil fueled anyway - you are not helping the environment by electrification of your gas appliances. The rest of Caber's comments are valid.

Unfortunately - the government of Canada is going to ram home legislation to force this upon everyone. You will be forced into it at some point. I wouldn't go voluntarily just yet.

[Dewey Cox]

Originally Posted by Jamie Black R/T

I could be wrong by I think the OP is referring to a on demand water heater. Not actually a heat pump.

What makes you say that?

[Trochu]

Without geothermal, would a HPWH even work in a typical home?

[FCLightning]

Originally Posted by Trochu

Without geothermal, would a HPWH even work in a typical home?

Air heat pumps can be efficient and effective. The question I would have about the overall efficiency of a HPWH would be that the ones I have seen have the evaporator on the unit rather than external to the house. So any heat you put into the water will be drawn from the air in they house - heat that will need to be replaced by your central heating unit.

[FCLightning]

Originally Posted by diesel44

Looking to take advantage of the Greener Homes Grant/Loan. Since my current hot water tank is past its prime, I am looking to change it. The grant/loan covers HPWH's only. Is this a good idea in Calgary. I will be changing my hot water tank anyway and 0% loan is nice to upgrade from standard tank.

What do the plumbers of A.O. think?

I think the question would be whether you have an electric or Nat. Gas unit currently. If you are switching from an electric tank the new unit would be considerably cheaper to operate - if you are switching from gas it would be considerably more expensive to operate.

[CaberTosser]

Originally Posted by FCLightning

Air heat pumps can be efficient and effective. The question I would have about the overall efficiency of a HPWH would be that the ones I have seen have the evaporator on the unit rather than external to the house. So any heat you put into the water will be drawn from the air in they house - heat that will need to be replaced by your central heating unit.

I have thought of this exact issue. A heat pump water heater may be desirable in warmer climates where the unit is acting as a bit of a de-facto air conditioner by scrubbing heat out of your house, but in areas with cold winters it would be drawing heat from the house that you had to provide in the 1st place, thus increasing the BTU demand on whatever that heat source happens to be. Another heat pump? A gas furnace? Electric?


The other thing to consider with a heat-pump style water heaters is its recovery rate. Typically, these will be way lower than a gas-fired water heater, so they try to buffer the difference with a large tank capacity to conceal the low recovery. Large households with many users might find the recovery rate to be lacking.

[dewalt18]

Caber makes a few very valid points. Without touching on the heater heating aspect, strictly from an HVAC perspective, heat pumps simply don’t make financial sense in the climate we live in. As far as heating your home with a heat pump goes, you’re limited to at the very most about -12° as an ambient. Now that sounds great, cause you’re not burning gas to heat your house when it’s right around the freezing point. But you are burning a considerable amount of electricity, the furnace blower to move air across the evaporator coil and through the house, as well as the compressor and too fan on the heat pump. Given the cost of natural gas vs electricity, I know I’d personally hear my burners come on.

[Jamie Black R/T]

Originally Posted by Dewey Cox

What makes you say that?

Ignorance mostly.

My bad.



Sent from my SM-G991W using Tapatalk

[Dewey Cox]

Originally Posted by Jamie Black R/T

Ignorance mostly.

My bad.



Sent from my SM-G991W using Tapatalk

It's ok.
I thought I made a mistake once too.

[FCLightning]

Originally Posted by dewalt18

Given the cost of natural gas vs electricity, I know I’d personally hear my burners come on.

Most heat pumps will operate with a COP around 3, which means they will use 1/3 the electricity to generate the same heat energy. Given that electricity at my house is currently 6 times the cost of Nat Gas per heat unit operating a heat pump would double my heating costs.


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[diesel44]

There is very little space to vent a power vented high efficiency water tank (Gas meter, AC, furnace vent, fresh air intake on opposite side of house). By removing the natural vented gas unit it will also eliminate the need for a chimney. I could then use the chimney space for a cable/wire chase to the roof for the solar system.

Just wanted to get some opinions on the HPWH since it is new to me.

Thank you for the posts so far.