by Rob Cox February 14, 2019
Everybody likes warm pool water, and I'm no exception, anything below 82° is too cold for me! For many people with a tight grip on the wallet, and I'm no exception, heating pool water can seem extravagant and expensive. Every pool owner knows that after the cost to buy a pool heater, there is the cost to install a pool heater, and then the cost to run a pool heater.
Solar heat is Free, but not so reliable or dependable. A few days of cold and rainy weather can put you back to square one. Pool heat pumps cost only half as much to operate than gas heaters, even though prices have never been lower for Natural Gas, but pool heat pumps cost twice as much to buy new, as compared to gas heaters.
On average, pool heaters cost $100-$300 per month to operate, depending on many factors, the top two being how big your pool is, and how warm you like the water.
It depends on how large your pool is, or how much surface area. Multiply your pool length x width to calculate surface area, and install a number of panels to equal 50-70% of the pool surface area. Use more if sun exposure is partially blocked during parts of the day, or you don't have a direct southern exposure for the solar panels. Inground pool solar heaters should also use a Solar Controller, to optimize and automate heating cycles.
Installing a solar pool heater can be done in one day by two people. Steps involve mounting the panels on a roof or rack, connecting plumbing from the pool equipment pad to the roof and back, mounting the Solar Controller and installing the sensors. PVC plumbing and fittings, and pipe connectors will need to be purchased separately.
Well now, solar heat is free! No cost to run a solar heater. Very little maintenance also, since there are so few moving parts - you may never need repair. Most pool solar systems will last about 10-20 years, depending on the material they are made from, before needing heavy repairs or replacement.
Heat pumps are not cheap to buy, especially as the units become bigger, and more advanced. Some pool heat pumps are known as chillers and can heat and cool the pool water. Heat pumps range in size from 50K Btu's up to 166K Btus. Units of 50K to 90K are usually sufficient for above ground pools, and for the average inground pool, 110K to 140K units are more suitable. Larger heat pumps are used with bigger pools or shady pools, or for high wind areas.
Installing a pool heat pump involves placing the unit on a heavy pad or slab, and plumbing the pool return pipe in and out of the unit. We recommend that a qualified electrician bring the power to the unit, as it needs a dedicated 40-50 amp circuit breaker, and often requires bringing more power to the pool equipment pad.
It depends on many factors, such as how much you are raising the temperature, outside air temperature, wind speed and whether you cover the pool or not. The largest factor however, can be the cost of electricity in your area. Some parts of the country are as low as 10¢/Kwh, while in other energy poor states (California, Hawaii and many New England states), charges can be as much as 40¢ per Kwh. The cost of electricity, or the national average has almost doubled since 2000.
Propane or Natural gas pool heaters are the same price. Gas pool heaters are sized according to the size of the pool, or if you have an attached spa that you want to heat to over 100 degrees. Most inground pools will install at least a 250K Btu gas heater, up to a 400K size. Cupro Nickel heat exchangers are recommended for salt water pools, and some states (California, Texas) require Low-NOx pool heaters or heaters with low nitrous oxide emissions.
Installing a gas pool heater involves placement and then plumbing, electricity and gas hook-up. Electricity is usually tapped off of the timeclock or outlet, a separate breaker is not needed. Gas hook-up should be done by a licensed gas contractor, and the gas meter (NG) may need to be upsized - call your gas supplier with pool heater BTU input, and they can install a larger meter if needed.
Like heat pumps, the cost to heat a pool with gas will vary, by pool size and temperature rise, and also by month. June-August will typically be the cheapest months to use gas heat, while earlier and later months with cooler temperatures will take drastically more gas to heat the pool. With lower costs for Natural Gas in recent years, the cost for propane is now 2-3x higher than NG.
Using a pool cover, either an automatic cover,solar cover or liquid solar blanket can reduce heat loss and evaporation by up to 75%, dramatically reducing energy expense. Lowering the thermostat a few degrees during periods of non-use also reduces the cost to run a pool heater.