Hi, I have a below ground pool in east of UK. It is heated by a heat pump (and has a solar cover on at night and when not used) and I normally keep it at 85F. I have always run the heat pump when the ambient temperature is hottest ie during the day, but with the rise in electricity prices would I be better off running at night, given that I pay 34p per KWH during the day and 18p per KWH at night? So, is there anybody clever enough out there to tell me whether the increased time I would probably need the heatpump on for at night, would be outweighed by the cheaper electricity price, and presumably there would be a cut off ambient temperature below which (or maybe above which?) I would be better running it in the day.
Heat pump on at night or during day- which is best if electricity is cheaper at night?
- Thread starter Greatsnoring
- Start date
- Apr 10, 2018
- 5,254
- Pool Size
- 18375
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45
Welcome to TFP!
I'd like a shot at the question though. From an efficiency standpoint, I don't think it matters when you heat the pool, particularly with a solar cover on to help with heat retention. I would take advantage of the greatly reduced electrical costs.
Best Wishes!
www.troublefreepool.com
Well, I'm out. But these guys are clever... @ajw22 @JamesW and know a bit about heating efficiency.
I'd like a shot at the question though. From an efficiency standpoint, I don't think it matters when you heat the pool, particularly with a solar cover on to help with heat retention. I would take advantage of the greatly reduced electrical costs.
Best Wishes!
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www.troublefreepool.com
- Jul 21, 2013
- 53,526
- Pool Size
- 35000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
I think it depends day to day on pool water temperature, daytime high temperature, nighttime low temperature, desired pool water temperature.
Depends where and when you start out and where and when you want to get to.
Depends where and when you start out and where and when you want to get to.
The answer is going to depend strongly on how much colder the ambient air is a night. Here in the US pool heaters are rated under 3 standardize conditions, 80 degree air, 80% humidity, 80 degree water, 80 degree air, 63% humidity, 80 degree water, and 50 degree air, 63% humidity, I expect that there are similar standards in the UK. Check the manual for your unit to see if you can find ratings. What you are looking for is "COP" or Coefficient of Performance. That is the ratio of the heat output to the electrical input. (ie a rating of 6 means that for every 1kWh of electricity you use the pool gets 6kWh of heat). The biggest factor in the efficiency is the temperature difference between the air and the water, typically the output is about 30% less with a 30F degree difference (air colder). Given the cost difference is nearly a factor of two my guess is that running at night will be better unless your night time temps are more than about 15-20 C cooler than the daytime.
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Each heat pump shows the performance relative to the conditions.
You have to compare your cost for electricity vs. the gain based on the conditions during the day and night.
You have to compare your cost for electricity vs. the gain based on the conditions during the day and night.