Exposing the Inefficiency of Electric Heaters for 15,000 Gallon Pools
When we first had our large, 15,000 gallon in-ground pool installed, we were eager to start enjoying lazy summer days swimming and lounging poolside. But we quickly realized that our rainy Pacific Northwest climate posed a challenge: how could we comfortably heat such a massive volume of water?
On our contractor's recommendation, we opted to install an electric pool heater. Electric heaters are often touted as an affordable and low-maintenance heating option. We figured it was a sensible choice for our large pool. Boy, were we wrong.
Understanding How Electric Pool Heaters Work
Before diving into why electric heaters are a poor match for large residential pools, it helps to understand what exactly they are and how they work to heat water.
Electric pool heaters use simple resistive heating elements, similar to the ones in your toaster or electric range. When switched on, electricity runs through the heating elements, causing them to warm up. A pump circulates pool water across the heated elements, transferring thermal energy to raise the water's temperature.
A heater's power is measured in BTUs, or British Thermal Units. The higher the BTU rating, the greater its heating capacity. Factors like climate, pump efficiency, and pool surface area determine how many BTUs are needed to maintain a comfortable swimming temperature.
Electric heaters are best suited for small pools, above ground pools, and hot tubs. Their low cost and simple operation make them a popular choice for these applications. But as pool size increases, their limitations become apparent.
The Challenges of Heating 15,000+ Gallons with Electric
We were oblivious to the downsides of using an electric heater for our massive pool. But after one long, frustrating winter we realized electric heaters are woefully inadequate for pools of this size.
Here are the main reasons electric heaters struggle with 15,000+ gallon pools:
- Limited heating capacity - Electric units max out around 450,000 BTUs, even on commercial models.
- High energy demand - Achieving sufficient BTUs requires incredibly high wattage.
- Low efficiency - Up to 75% of electric heat is lost in the process.
- Inadequate for cold weather - Electric models can't keep up in frigid conditions.
- Expensive to operate - Heating costs easily exceed $200+ per month.
In comparison, gas heaters and heat pumps are much better equipped for pools of this size, as we'll explore later on.
Properly Sizing Electric Heaters for 15,000 Gallons
They say ignorance is bliss. We went into installing our electric heater blindly, not realizing its capacity was woefully insufficient for our pool.
To determine the right electric heater size, you need to calculate the minimum BTUs required. The standard formula is BTUs = Volume in Gallons x Temperature Rise x Heat Loss Factor.
For our 15,000 gallon pool in chilly Washington, we actually needed around 200,000 BTUs for adequate heating. Our 30kW electric heater only provided 102,000 BTUs - no match for frigid Northwest winters.
Getting to 200k+ BTUs would require multiple enormous commercial heaters, at a prohibitive cost exceeding $5,000. And operating multiple units multiplies already-high energy bills.
Comparing Energy Efficiency Ratings
After battling sky-high electricity bills, we understood why electric models are scorned as energy hogs.
Electric resistance heating has a COP of 1.0 - the lowest efficiency rating possible. Up to 75% of the energy consumed is wasted in the heating process.
Compare this to heat pumps, which use compression to extract ambient heat. Quality heat pump systems have COP ratings from 4.0 to 6.0. Their efficiency is 3 to 4 times higher than electric resistance!
Propane and natural gas also edge out electric units in efficiency. Less heat energy escapes through the combustion process. This equates to lower costs for similar BTU output.
The Hidden Operating Costs
Electricity to power our undersized heater cost us nearly $300 some months. We chalked it up to the price you pay for a pool in the Pacific Northwest.
In reality, we were paying the price for inefficient electric heating. Even in warmer climates, costs typically exceed $200 monthly for 15,000 gallon pools.
Gas heaters run about $150 monthly to operate, while heat pumps can be as little as $100. In colder regions, electric heating costs can be a whopping 2 to 3 times higher!
Factoring in the purchase price, lifetime costs for an electric heater are astronomical compared to more efficient options. Our expensive mistake taught us just how vital energy efficiency is for pool heating.
More Limitations of Electric Heaters
Besides inefficiency, electric heaters have a few other drawbacks that make them a poor match for 15,000+ gallon installations:
- Slow heat up times - Electric elements lag behind gas and heat pumps.
- Temperature fluctuations - Struggle maintaining consistent water temp.
- Short lifespan - Last only 5-10 years before needing replacement.
- Poor automation integration - Work with limited control systems.
Modern heat pumps and gas heaters avoid these pitfalls while offering superior efficiency. It's a night and day difference.
After analyzing the facts, it's clear electric heaters are a poor choice for 15,000 gallon residential pools. Their limited heating capacity and dismal efficiency make operating costs prohibitive.
For pools of this size, gas or propane powered heaters are far more cost-effective. Heat pumps also offer excellent efficiency and reasonable heating expenses.
Don't make the same mistake we did - the pool contractor didn't warn us properly about electric heaters. Make sure to take pool size into account when selecting a heating system. Get multiple quotes comparing electric, gas and heat pump operating costs before deciding.
We ended up replacing our electric heater with a high-efficiency heat pump. Finally, we can enjoy our large pool affordably year-round - even in frigid weather. Don't settle for an inefficient electric heater for your 15,000+ gallon pool. There are much better options available that will save you money in the long run.