Starting in the first century, the Roman Empire started heating pools via wood-burning furnaces beneath the floor. Nowadays, options for heating swimming pools are a bit more efficient: homeowners usually choose either a gas/propane pool heater or an electric heat pump to achieve the perfect temperature.
Whether you're designing a brand-new swimming pool, or adding heat to your existing pool, you're definitely searching for the option that works best for your upfront budget, long-term energy expenses, and lifestyle.
What fits in better with your budget — a pool heater or a heat pump? Which is better suited to your climate? Which device is more effective for a combination pool and spa? Let's take a closer look at the pros, cons, and comparisons between pool heaters and heat pumps, so you can decide what will work best for your swimming pool.
Gas or Propane Pool Heaters: Quick, Powerful Heat
As the most popular option for warming swimming pools, many people are familiar with the classic pool heater. Fueled by either propane or gas, newer water heaters should be chosen to fit the size and energy-efficiency needs of your swimming pool.
How Pool Heaters Warm Your Pool
Inside a pool heater, either propane or natural gas burns inside the heater's combustion chamber, generating heat. Water from the pool is drawn into coils inside the pump. As the water passes through the heated coils in the chamber, it heats up and is returned to the pool. This process repeats continuously, quickly getting your pool or spa up to the desired temperature.
Benefits of a Pool Heater
- Lower upfront cost. Gas or propane-powered pool heaters generally cost a bit less upfront than a heat pump, which makes them an attractive option for many homeowners.
- Good for heating a pool quickly. Do you want a pool heater that will get your pool up to the desired temperature quickly for the occasional pool party? In that case, a pool heater is probably a good option for you.
- Better in cooler climates. Because pool heaters create their own source of heat inside the combustion chamber, they're usually the best option for people who live in cooler climates where the outside temperature regularly dips quite low.
- Awesome choice for hot tubs. If you have a Jacuzzi or hot tub that you want to get up to high temperatures, then a propane or gas water heater is probably the best option.
Drawbacks of a Pool Heater
- May not be as energy-efficient. Pool heaters work quickly to achieve the effect you need. However, because they need to generate quite a bit of power to quickly heat a pool, they may not be as efficient as the slow-and-steady heat pump.
- Higher operating costs. The cost of natural gas or propane used to fuel a pool heater can add up quickly, especially if used regularly.
- Not as great for frequent use. If you plan to use and heat your pool every single day — rather than for just a few weekends per year — then you might want to consider a heat pump instead (depending on climate.)
Electric Heat Pumps: Slow Yet Steady Efficiency
As opposed to gas or propane, heat pumps use electricity to heat water. Instead of creating heat through burning fuel, heat pumps capture heat from the surrounding air, then transfer that heat to your swimming water.
How Heat Pumps Warm Your Pool
To begin the process of transferring heat, the pool pump's fan sucks in the air outside your pool. When this air passes over the evaporator coil in the heat pump, a special liquid within the coil absorbs the heat and becomes a gas. After passing through the heat pump's compressor and condenser, the gas's heat increases. Meanwhile, your pool pump works to circulate cool pool water into the heat pump, where it's heated by the hot gas in the condenser and then is returned to the pool. Then, the process repeats.
Benefits of a Heat Pump
- More efficient over time. Though they often cost more upfront than water heaters, they're generally more cost-efficient over time because they require less energy (in warm climates).
- Works great in warm climates. Because a heat pump works by transferring heat from outside air into the pool, it's a great option for warmer climates where the air stays warm year-round (above the 40 to 50 degree range).
- Great for frequently-used pools. A heat pump might not heat water as quickly as a gas or propane heater, but it's a great option for keeping a steady set temperature in a pool. This makes it desirable for people who plan to use their pool very frequently.
- Lower operating costs. Because they rely primarily on ambient air temperature vs. a constant flow of gas fuel, the cost to operate a heat pump is considerably lower than a traditional gas heater.
Drawbacks of a Heat Pump
- Works slower than a pool heater. Because the heat pump doesn't generate its own heat through burning fuel, it generally works slower than a gas or propane-powered tank. For this reason, it's not quite as efficient when heating a Jacuzzi or a hot tub.
- Not as efficient in colder areas. If your outside temperatures regularly fall under 40 to 50 degrees during pool season, a heat pump may not be your best option.
Pool Heaters vs. Heat Pumps: Questions You Need to Ask
Buying a heater for your swimming pool takes some deliberation. Both heat pumps and water heaters are excellent options, and neither is intrinsically better than the other. When you're making your decision, try to ask yourself the following questions:
- How important is quick, on-demand heat? Both water heaters and heat pumps can heat your pool to the temperature you want, but water heaters are generally a little quicker.
- What sort of climate do you live in? In a cooler, northern climate, a gas or propane water heater might be the best choice. In a warmer, southern climate, a heat pump is probably the more efficient choice.
- What's the cost of natural gas vs. propane in your area? If you choose to go with a gas heater, you'll definitely want to take a close look at the relative costs and availability of gas and propane in your community.
- Is it more important to save up-front, or over the long-term? In general, since it's transferring rather than creating heat, a heat pump uses considerably less energy in the long-term. However, it may cost more upfront.
If you're not sure which heating method suits your needs better, it's a great idea to talk to a professional. An expert in pool installation can talk you through the climate factors, efficiency questions, and lifestyle needs that will shape your decision.