Effect of the carbon tax on pool heating in Canada - should you still buy a gas heater?

[wayner]

[Note - I am not debating the pros and cons of the carbon tax or the politics of the situation. I am just starting a discussion on whether it makes sense to buy a new natural gas pool heater in Canada, assuming that the carbon tax regime stays the same as it is today.]

I am in Toronto and have a natural gas heater for my pool. In Canada we have a carbon tax regime that is escalating over time. Currently the tax is 12.4c/m^3 which is almost equal to the cost of the gas itself at 15.8c/m^3 (my rate in August with Enbridge). There are other delivery charges as well on the bill my current variable charges for gas are as follows so my current gas charges are about $0.16 for Gas, $0.124 for the carbon tax and about $0.13 for delivery, and other variable charges. There is also a a fixed cost of $23 per month.

Over the next few years the carbon tax is scheduled to go up. In 2030 that tax is supposed to go up to $0.324/m. So the price paid for natural gas will be up by 50% by 2030, assuming that the actual gas cost stays the same.

Therefore, does it still make sense to be buying a gas heater in Canada? Should we be looking at moving towards heat pumps, even though they are much slower and less effective in heating a pool in the shoulder seasons? I haven't heard much discussion of this, but that carbon tax will really bite in the future when it hits that amount. It is already 29% of the variable price of gas and will rise to over 50% in 2030, given current assumptions.

 

[PoolGate]

You'll lose your shoulder months especially in your location. Perhaps propane? No good solution for you with artificial price increases you never know if the rise will ever end. Vote better leaders perhaps?

 

[JoyfulNoise]

You have to compare your electrical rates to your gas rates and then forecast at what point they cross over and how much of a premium you’re willing to pay for those BTUs.

If you generate your own electricity with solar panels then that can offset some of the costs associated with an HP. Solar water heaters can also benefit here as the incremental cost of the energy needed to pump water up to a roof line shouldn’t be too bad.

 

[mas985]

Should we be looking at moving towards heat pumps, even though they are much slower and less effective in heating a pool in the shoulder seasons?

While the efficiency of a HP decreases with outdoor temperatures, even temperatures as low as -20C, they can still be more efficient than a NG heater.

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Note: Some pool HP will not run below 45F.

 

[JoyfulNoise]

There was an outfit a long time ago here in Tucson that routinely installed a solar PV array with solar heating coils and I believe they used Pentair tech (SunTouch) to control both heat sources. It was advertised as a “Green Tech” for heating a pool fast and efficiently but the company didn’t last very long as the PV installer market here got saturated and gas is still pretty cheap compared to how much installation cost you’d have to make up for a new install.

That might be the route Canadian pool owners have to go - install solar PV to offset the costs of running a heat pump and supplement with solar water heating.

Oh, and there’s also the HotSpot FPH systems that scavenge waste heat from AC compressors.

 

[JamesW]

Maybe install a geothermal heat pump.

The upfront cost can be high, but the systems can be worthwhile.

Maybe do a geothermal heat pump for the home as well to get more utility from the ground loop.

You can probably put two loops in for about the cost of 1 or slightly higher.

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[wayner]

You'll lose your shoulder months especially in your location. Perhaps propane? No good solution for you with artificial price increases you never know if the rise will ever end. Vote better leaders perhaps?

If you have a solar cover I would think the problem would be more in the spring. I got a solar cover this year and through September I would heat the pool up to 84 on the weekend and shut the heater off on Sunday night. Through Friday the temperature stayed around 77 - but this was an unusually warm and sunny September. So I imagine it wouldn't be an issue for a heat pump to get it back up to 84 if I turned it on Friday night.

But when I open the pool in May it may take longer to get it up to 84 for the first time.

 

[wayner]

There was an outfit a long time ago here in Tucson that routinely installed a solar PV array with solar heating coils and I believe they used Pentair tech (SunTouch) to control both heat sources. It was advertised as a “Green Tech” for heating a pool fast and efficiently but the company didn’t last very long as the PV installer market here got saturated and gas is still pretty cheap compared to how much installation cost you’d have to make up for a new install.

That might be the route Canadian pool owners have to go - install solar PV to offset the costs of running a heat pump and supplement with solar water heating.

Oh, and there’s also the HotSpot FPH systems that scavenge waste heat from AC compressors.

Those hotspot systems make a ton of sense since all summer my air conditioner is pumping heat out of my house and a natural gas heater is heating my pool. It makes sense to move the heat from the house to the pool. I have PV panels on my house and the electricity produced is sold back into the grid due to the pricing regime here in Ontario when I installed those panels back in 2015.

I also have/had evacuated tube solar panels on my roof. My water would get pumped onto the roof, through the tubes and then back to my pool. But I had some issues with it and the person who installed it is no longer around. But it always caused bubbles to be injected into my returns - I am guessing because there wasn't enough back pressure as the return from the roof was coming down about 10-15 feet. So that system has been bypassed for a couple of years. But it really helped reduce the need for using the natgas heater.

 

[JoyfulNoise]

Those hotspot systems make a ton of sense since all summer my air conditioner is pumping heat out of my house and a natural gas heater is heating my pool. It makes sense to move the heat from the house to the pool. I have PV panels on my house and the electricity produced is sold back into the grid due to the pricing regime here in Ontario when I installed those panels back in 2015.

I also have/had evacuated tube solar panels on my roof. My water would get pumped onto the roof, through the tubes and then back to my pool. But I had some issues with it and the person who installed it is no longer around. But it always caused bubbles to be injected into my returns - I am guessing because there wasn't enough back pressure as the return from the roof was coming down about 10-15 feet. So that system has been bypassed for a couple of years. But it really helped reduce the need for using the natgas heater.

Seems like you could potentially do a heat pump without much effort if the PV is large enough to supply power for it. Screw the grid and keep all that extra energy for yourself!

Bubbles fro the solar heaters sounds like the vacuum relief valve was probably bad and air into the system. Solar heating always seems like a good idea on paper but it certainly has its downsides.

Nothing is ever going to replace the ease and speed at which a gas heater can operate. But if circumstances are going to force you off gas or severely limit its use, then at least you have some viable options.

 

[wayner]

Seems like you could potentially do a heat pump without much effort if the PV is large enough to supply power for it. Screw the grid and keep all that extra energy for yourself!

I could do that, but I get 38c/kWh for the electricity I produce and my price to buy is from 2-24c/kWh, plus about 4c in transmission and distribution. So it makes way more sense to sell my power into the grid.

I don't think I will replace my gas heater in the short term, but when it dies I will likely get a heat pump. My original heater was a Jandy gas heater - that lasted 11-12 years. That was replaced with a Raypak gas heater 4.5 years ago. So when the Raypak dies I will likely go with a heat pump.

edit - Does anyone have a calculator that let's you do comparative pricing for gas vs electric heaters? Given my very low overnight electrical rate I am wondering how much I will save going to a heat pump. In Ontario we have a rate system called ULO - this is targeted at EV owners. The rate from 11pm-7am is 2.4c -plus T&D fees, etc. But that may make it very cheap to heat my pool with a heat pump.

 

[JamesW]

I could do that, but I get 38c/kWh for the electricity I produce and my price to buy is from 2-24c/kWh, plus about 4c in transmission and distribution.

Connect the supply to the output and sell them their own electricity.

 

[mas985]

edit - Does anyone have a calculator that let's you do comparative pricing for gas vs electric heaters?

Here is a heat transfer spreadsheet that will allow you to estimate costs for NG vs HP. It will also determine heat loss from evaporation, convection, radiation and conduction as well any heat added by solar.

Release - Google Drive

drive.google.com

 

[JamesW]

Diamonds are made of carbon, are they going to tax diamonds as well?

 

[wayner]

Here is a heat transfer spreadsheet that will allow you to estimate costs for NG vs HP. It will also determine heat loss from evaporation, convection, radiation and conduction as well any heat added by solar.

Thanks, I took a quick look at it - FYI Excel is complaining about a circularity in cell C185.

How do you determine, or look up, the Heat Pump COP?

 

[mas985]

You need to enable circular calculations because it is an iterative approach that assumes infinite cycles of the same day/weather in order to find an equilibrium solution. In Excel, go to File, Options, Formulas, Check "Enable Iterative Calculation".

COP is usually published by the manufacture but it is dependent on the temperature difference between the water and the air. What make/model are you considering?

 

[JamesW]

The manufacturer will publish the metrics for the heat pump.

https://www.pentair.com/content/dam/extranet/nam/pentair-pool/residential/heaters/ultratemp/ultratemp/ultratemp-heat-pump-installation-and-users-guide-en-fr-sp.pdf

 

[wayner]

Not sure - I have a Raypak gas heater now that is 266,000 BTU. Maybe around 120,000 BTU. I realize that it will take twice as long to heat, but as long as I keep it covered with a solar cover that doesn't seem to be a big deal to me. I would plan to primarily run the heat pump at night when my power is very cheap.

This isn't something that I would do right away, I am just trying to figure out the difference in operating costs as the price of gas goes up, and when my heater needs to be replaced.

 

[mas985]

If you are interested in a worst case, then just use 4.0 for the COP.

Also, if you are only interested in costs and not the resulting water temperatures, you can use the simplified version of the SS called "Heaters". However, you will need to enter both the target and nominal (unheated) water temperatures as well as the solar cover heat gain which is what the other model calculates. But at least it can give you a rough answer.

But in general, if the cost of NG in $/Therm is >6x the cost of electricity in $/kwh, then the HP will win. Assumes a COP of 4 and NG efficiency of 85%.

 

[JamesW]

I would plan to primarily run the heat pump at night when my power is very cheap.

The heat pump won't work as well at night since it is colder.

This will offset the cost difference somewhat.

For example, the COP might be 5.9 during the day and maybe 4 during the night.

How much is the power cost difference?

 

[wayner]

The heat pump won't work as well at night since it is colder.

This will offset the cost difference somewhat.

For example, the COP might be 5.9 during the day and maybe 4 during the night.

How much is the power cost difference?

Pretty large differential. In addition there are about 4c/kWh in other charges like distribution, transmission, etc and sales tax of 12%. But those don't vary with time. This rate structure was put in place to encourage EV owners to charge overnight. I have put a timer on my spa so that it turns on at 11pm and turn off at 3pm.

Period	Time	Rate
Ultra-low overnight	Every day from 11 p.m. to 7 a.m.	2.4¢ per kWh
Weekend off-peak	Weekends and holidays from 7 a.m. to 11 p.m.	7.4¢ per kWh
Mid-peak	Weekdays from 7 a.m. to 4 p.m. and 9 p.m. to 11 p.m.	10.2¢ per kWh
On-peak	Weekdays from 4 p.m. to 9 p.m.	24.0¢ per kWh