Warm Up Your Pool (Eco-Friendly & Cheap Solutions)

Nothing spoils a swim like ice-cold water. The good news is you don’t need to break the bank (or the planet) to keep it cozy. For small to medium sized pools, solar tricks and simple covers often work wonders. For example, covering the pool at night can trap warmth, and a sturdy bubble “solar blanket” can boost water temperature by several degrees. Solar-powered solutions are the most cost-effective ways to heat a pool and are inexpensive in themselves. Even better, a pool cover also cuts evaporation – the number 1 culprit for heat loss – so you lose far less warmth overnight.

Most people swim comfortably around 78–82°F, so our goal is just to raise the water to that range. For a small to medium sized above ground pools, a modest increase (say +5–10°F) goes a long way. A quality solar blanket (bubble-style cover) can do this on a sunny day.

These bubble-wrap covers are cheap and cut heat loss dramatically. They’re extremely easy to install – just spread it over the pool when it’s not in use – and eco-friendly since they use no power at all. (Just remember to remove it when swimming!).

• Key tips: Always use a pool cover at night to trap warmth. Run your pump during the warmest part of the day to circulate heat. Keep the water filter clean for best flow (and heating efficiency). And minimize shade on the pool – sunlight is your friend here.

  
  

DIY Solar Heating Hacks

If you’re handy, you can build your own solar heater for very little money. The classic “black hose” trick is one of the cheapest solutions imaginable. You simply coil a long black garden hose in the sun, hook it up to your pool pump or a small pump, and pump water through the hose back into the pool. As the sun heats the hose, it warms the water inside, delivering a flow of warm water back to your pool.

In practice, you’d buy (or reuse) about 50–200 feet of black poly tubing and mount it on a flat board in a sunny spot. For example, use 200 ft of ½″ black irrigation hose coiled on a plywood tray. You can paint the board black or lay a black tarp underneath to capture extra heat and even cover the coil with a clear plastic sheet to trap heat like a mini greenhouse!

Building this won’t cost you much. It won’t match a propane heater’s power, but it’s very cheap to run (just a bit of electricity for the pump). Although a DIY coil is not nearly as powerful as gas/electric heaters, it is extremely affordable to run and build, especially on an above-ground pool. In short:

• Cost: Very low

• Efficiency: Mild – expect only a few degrees of warming per sunny day. (Great for a little extra warmth.)

• Ease: Easy to set up yourself. Just hook hoses and start the pump.

• Eco: Excellent – uses only solar energy and a low-power pump.

  
  

You can also try placing solar mats or panels designed for pools. These are ready-made collectors that plumb into your filter. For instance, an inexpensive Intex solar panel can raise water by about 5–9°F in sun. A couple of those panels give a quick temp bump on a sunny day. There are even floating solar rings/domeshaped heaters (inflatable bubble discs) that you just toss on the water. These are literally designed for above-ground pools and “work very well” according to reviews. (They won’t replace a heater, but they’re easy to use and maintain a bit of heat.)

Heat Pumps: Efficient Electric Heating

When you need more consistent heat (say for cooler mornings or a slightly longer season), a heat pump is a smart middle-ground. A pool heat pump uses electricity to extract heat from the air and dump it into the water. It has a high coefficient of performance (COP) – often 300–600% efficiency – meaning for each kW of power in, it delivers 3–6 kW of heat. In practical terms, once the pump warms the pool a bit, it maintains temperature very cheaply.

Installation is more involved (electric hook-up and plumbing), but many units are DIY-friendly for above-ground pools. Once in place, however, they run quietly and reliably. Heat pumps also have the eco edge of no direct on-site emissions – they just use grid electricity. (Of course, you’ll still use some electricity, but this can even be offset by solar panels, making it quite green.) The catch: heat pumps are most effective when the air is above ~50°F. Below that, their efficiency drops. So, they’re great for summer and shoulder seasons in mild climates.

• Cost: High

• Efficiency: Very high (COP ~4-6, so cheap to run after warm-up).

• Eco: Medium/High (no combustion, but uses electricity).

• Installation: Requires setup (electric outlet and plumbing).

  
  

Propane/Gas Heaters: Fast, But Costly!

For quick heating on demand, fuel-fired heaters (propane or natural gas) work regardless of weather. A propane heater pumps out a lot of BTUs, so it can raise water temperature fastest. This can be handy if you only use the pool sporadically or want on-the-spot heat.

However, the fuel bills add up. Propane runs about $3 per gallon, and a medium-size heater can burn ~3 gal/hour (that’s roughly $6/hr for a big pool) – even if your pool is much smaller, expect a few dollars per hour of heat. In short, propane is fast but expensive to operate.

Propane heaters are fuel-rich and effective even in cold weather, but the downside is fuel costs and CO₂. Propane is cleaner-burning than oil, but it still releases CO₂ when burned.

• Cost: Medium

• Efficiency: High output (heats fast), but uses expensive fuel.

• Eco: Low (burns fossil fuel; emits CO₂).

• Installation: Requires a propane tank or gas line.

Quick Reference Table

Method	Upfront Cost	Heating Boost/Efficiency	Eco-Friendliness
Solar Cover/Blanket	Low – very low	Modest temp rise (+3–10°F on sunny days); primarily prevents heat loss	Very high. No energy used; cuts evaporation (saves water/chemicals).
DIY Solar Coil (Black Hose)	Very low	Small warming effect in sun; very gradual +2–5°F	Very high. Uses only solar heat; minimal electricity for pump.
Solar Heater Pad/Panel	Low	Moderate (+5–9°F in sun for an 8,000 gal pool; likely more effect on 2,000 gal)	High. Powered by sun. (Similar to covers in impact.)
Heat Pump	High	High efficiency (COP ~4–6) – provides steady heat	Moderate. Uses electricity (zero on-site CO₂); very efficient so less total energy.
Propane/Gas Heater	Medium	Very fast heating (e.g. 100K–200K BTU); but high fuel use	Low. Burns fossil fuel (CO₂ emissions); fuel costs add up.
Electric Resistance	Low	Low efficiency (COP ~1; essentially 1 BTU per BTU) – high $/energy, so rarely recommended.	Low. Very high electricity use; generally poor eco.

(Values are approximate for a ~2,000 gal pool. Exact results depend on pool size, climate, usage, and installation.)

Putting It All Together

For a small to medium sized above-ground pool, the most bang-for-your-buck methods are usually solar covers and DIY solar. Start with a good solar blanket and some sunshine. Even floating solar rings can help maintain heat. These cost very little and have zero operating cost. If you need more heat (especially in cooler weather), consider a mid-size heat pump – it’s pricey up front but very cheap to run and eco-friendly over time. Propane or gas heaters do heat quickly, but only use them if you really need fast warm-up on demand (keeping in mind the fuel bills and CO₂).

Finally, remember the basics: cover it at night, run the pump in sun, and keep the pool clean – these simple steps alone save a surprising amount of heat. With a little planning and the right combination of methods, you can enjoy a warm pool without a sky-high bill!