Oasis heat pump efficient to 40*?

While a heat pump may "work" if the air is x degrees cold it is still only going to heat it a couple of degrees over the water temp which could be colder than x to start with So I'm leery of how much help it will be in 40 degree weather.

Maddie :flower:
 
While a heat pump may "work" if the air is x degrees cold it is still only going to heat it a couple of degrees over the water temp which could be colder than x to start with So I'm leery of how much help it will be in 40 degree weather.

Maddie :flower:

Yea, I guess what I'm wondering if it is actually any more efficient at cold temps than other models. Is it even physically possible?
 
Heat pumps work by extracting heat from the outside air. As the outside air gets colder there is less heat contained in it , making it harder to extract the same amount of heat gained at higher temperatures. Therefore you have less heat gain on the side you are trying to raise the temperature. That is why in areas where you are using a heat pump to heat your house that sees outside temperatures that are regularly below 32 degrees, you need an auxiliary heat source to augment the heat pump as it will not keep up with the heat loss at lower temperatures. As the outside air gets colder the heat pump BTU output drops even though the heat pump will work at a lower outdoor air temperature (although with more frequent defrost cycles during which you are actually cooling the media that you are trying to heat) . It is still very efficient at lower temperatures but the heat output drop off will not allow it to do the job that you want it to do.
 
Heat pumps have their place but not in colder climates. You need temps in the 70's for it to produce at a good pace. In the shoulder seasons, early spring and fall when temperatures are low it'll work but very slow. In your climate the best way is NG heaters. Sized right can produce 1-2 degrees an hour.2
 
So my oil furnace is in a utility room about 10 ft from the heat pump. The furnace room is typically rather warm in the high 80s/low 90s. If I moved it inside, how much better would it keep up with cold water ? Would it be enough to overpower it or still struggle ? If it could handle the warmup I would definitely use it like a gas heater to warm up on short notice for a weekend party.
 
Heat pumps have their place but not in colder climates. You need temps in the 70's for it to produce at a good pace. In the shoulder seasons, early spring and fall when temperatures are low it'll work but very slow. In your climate the best way is NG heaters. Sized right can produce 1-2 degrees an hour.2

I know heat pumps won't be fast, but to me, consistently warm is more important than heating quickly for a weekend swim or something. The Raypak calculator says it could keep our pool at 82* from Apr to Oct and save us a couple hundred over natural gas. We're also planning on getting solar in the near future which makes the heat pump more appealing to me. I was considering coupling it with a solar hot water system like Heliocol since we get 300+ days of sun and have a southern exposure.
 
As the outside air gets colder the heat pump BTU output drop

Yea, that I understand, but is there a chart that each company has that shows the BTU at specific temperatures? Could the Oasis actually produce more BTUs at lower temps or is that pretty much the same across all brands since there is only so much heat in the air to extract? It seems like most are rated to the produce their listed BTUs down to 50? Our march/april and oct/nov is going to be in the mid 40s often so if this one could eek out a few more BTUs at slightly lower temps it'd be a big help.

People on this forum seem to like the Raypak calculator and it says it could heat our pool to our desired temp April-Oct and save us a few hundred over nat gas. Is their calculator pretty accurate?
 
So my oil furnace is in a utility room about 10 ft from the heat pump. The furnace room is typically rather warm in the high 80s/low 90s. If I moved it inside, how much better would it keep up with cold water ? Would it be enough to overpower it or still struggle ? If it could handle the warmup I would definitely use it like a gas heater to warm up on short notice for a weekend party.

You would not believe how much heat a pool takes, or how little there is in air! It would make that utility room arctic in 10 minutes.
 
Yea, that I understand, but is there a chart that each company has that shows the BTU at specific temperatures? Could the Oasis actually produce more BTUs at lower temps or is that pretty much the same across all brands since there is only so much heat in the air to extract? It seems like most are rated to the produce their listed BTUs down to 50? Our march/april and oct/nov is going to be in the mid 40s often so if this one could eek out a few more BTUs at slightly lower temps it'd be a big help.

People on this forum seem to like the Raypak calculator and it says it could heat our pool to our desired temp April-Oct and save us a few hundred over nat gas. Is their calculator pretty accurate?

Pentair has a Heat Pump temperature performance chart on their website. As you can see it is linear. You can extrapolate it down to 40. I doubt the Oasis performance is any better.

At 40F BTU is about half the rated output.

 
  • Like
Reactions: nobueno

Enjoying this content?

Support TFP with a donation.

Give Support
You would not believe how much heat a pool takes, or how little there is in air! It would make that utility room arctic in 10 minutes.

Makes sense. Thanks. The air coming off the top of my heater is not only ice cold but tons of cfm too.
 
You need to post the specs on your pool in order to have a meaningful discussion about using a heat pump for your pool. Do not confuse efficiency with ability to heat a medium to a specific temperature ( heat output). Heat Pumps are very efficient at all temperatures but quickly lose heat output as the temperature of the medium you are extracting heat from drops. You are also somewhat limited by the size of the heat pumps available for a pool. You must also realize that in order for a heat pump to work that the pool circulation pump must be running thereby decreasing the efficiency of the heat pump by adding the cost of the electrical energy of the circulating pump to the cost of the heat produced. We would also need to know the goals you are trying to achieve i.e. pool water temperature preference when you are swimming. Whether or not you are using a pool cover. Is the pool indoor or outdoor? What is the surface area of the pool? What is the total water volume of your pool? It is difficult to give a quantitative answer without knowing the specifications and variables.
 
You need to post the specs on your pool in order to have a meaningful discussion about using a heat pump for your pool. Do not confuse efficiency with ability to heat a medium to a specific temperature ( heat output). Heat Pumps are very efficient at all temperatures but quickly lose heat output as the temperature of the medium you are extracting heat from drops. You are also somewhat limited by the size of the heat pumps available for a pool. You must also realize that in order for a heat pump to work that the pool circulation pump must be running thereby decreasing the efficiency of the heat pump by adding the cost of the electrical energy of the circulating pump to the cost of the heat produced. We would also need to know the goals you are trying to achieve i.e. pool water temperature preference when you are swimming. Whether or not you are using a pool cover. Is the pool indoor or outdoor? What is the surface area of the pool? What is the total water volume of your pool? It is difficult to give a quantitative answer without knowing the specifications and variables.


We're still in the planning phase but we're pretty set on a vinyl 16x40, approximately 22k gallons, autocover, swimming temp around 82, outdoors, full sun southern exposure, protected from wind on 3 sides. Average high in Apr and Oct is above 60 and lows hover around 40 those months and that's how long I'd like our season to be.

Regarding the circulation increasing the operating cost, we're planning on a variable speed pump and a SWG so I figured it would be running 12+hrs a day either way.
 
Last edited:
A heat pump does not sound like a viable solution in your situation and climate. Your pool will hold 183,480 lbs. of water requiring a heat pump of 183,480 BTUs to raise the water temperature 1 degree F per hour in ideal conditions. Most high capacity pool heat pumps top out at 140,00 to 145,00 BTUs at ideal conditions giving you slightly greater than 3/4 of a degree temperature rise per hour at 80 degree outside air temperature or better. As the outside air temperature drops you will lose ~ 12-15% of the total output for every 10 degree drop in outside air temperature causing an even lower fractional temperature rise per hour. The greatest volume of heat transfer from the heat pump to the water will occur at the greatest temperature differential between the water and the heat pump heat exchanger i.e. at the highest pump speed. Running the pump at a lower speed will result in the latter passes of the heat exchanger seeing a higher water temperature thus resulting in a lower total BTU output (though I can't give you a quantitative answer as to what that loss would be). In order to get definitive and quantitative answers you would need to talk to a Thermal Engineer as I only have a background in pre-engineering and HVAC.
 
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.