Having a heated swimming pool means we can enjoy our garden for more months of the year. However the actual cost of a gas-fired pool heater depends on many factors and hence we are unable to provide a direct answer. What’s we’ll do instead is examine the factors first. Then we’ll provide a few pricing tips you can apply to your particular situation.
A gas-fired pool boiler is still the best solution because you don’t have to depend on the weather as you would with solar panels. However, the weather does still affect the system. That’s because of your pool’s location in terms of shading, wind chill and other factors.
Therefore, your best solution is to install a slightly more powerful natural or LPG gas appliance than you need. Then you can turn the heat down if the pool feels too warm, although you certainly cannot turn it up above maximum.
How Gas-Fired Pool Heaters Work
Gas pool boilers use LPG or natural gas as heat source. The pool pump circulates the water for aeration and filtration. This passes through the filter before entering the heating element. The heat from the combustion chamber exchanges through the walls of the metal tubing through which it flows.
Gas boiler-heated pools are popular because they warm the water quickly compared to solar and heat pumps that take ages. Just perfect for a week of sunny weather with the spring bulbs popping up all over the garden!
Size, Efficiency, and Cost the Main Criteria for Choosing Pool Boilers
Sizing a gas pool heater is a job for a trained professional. They also need to be Gas Safe registered for your safety’s sake and to remain within the law. In headline terms, sizing involves relating pool surface area and average ambient temperature. However wind exposure, humidity levels, and cool night temperatures also play a role.
Hence a pool on the exposed Scottish north coast will definitely require a larger pool heating appliance than one in the countryside just north of Brighton. Engineers rate pool heaters according to their Btu outputs. Pool boilers in the UK range from 75,000 to 450,000 of these British thermal units.
Calculating Approximate Heater Size for an Outdoor Pool in 5 Steps
- Decide how warm you would like the pool to be when the boiler’s in use
- Determine the average temperature for the coldest month you will swim
- Subtract the average air temperature from the desired pool temperature
You now know the temperature rise you will need to achieve. Next 4) calculate the pool surface area in square feet. Finally 5) calculate your Btu output requirement using this formula:
Pool Surface Area x Temperature Rise x 12
This formula assumes (a) a 0.5 to 0.7 ºC temperature rise per hour, and (b) an average 3.5 mph wind speed at the pool surface. Energy.Gov suggests doubling the result if you need a 1.1 ºC temperature rise per hour.
Determining the Efficiency Rating of a Gas Pool Boiler
It’s equally important to have a pool heater that’s energy-efficient so we don’t spend more money than necessary. All new swimming pool heaters undergo a standard test to determine their energy-efficiency in terms of their Btu rating.
This energy-efficiency rating expresses their ratio between energy input and achieved output. For example, a 75% ratio means 25% of your gas is fruitlessly spent. This energy-efficiency rating should appear on the appliance’s name plate. If this data is missing, don’t even consider purchasing it.
Modern pool boilers have ratings between 89% and 95%. If you have an old boiler you may be wasting money on gas. Use the following formula to determine the potential saving if you know your current heater’s rating.
Current Annual Cost x [1 – (Current Efficiency ÷ New Efficiency)]
Why It’s Important to Do Regular Maintenance
Follow the manufacturer’s advice to keep your pool in tip-top condition with optimised energy efficiency. Ensure a registered Gas Safe engineer installs it so it works properly from the beginning. With good care your new appliance could last five, and even more years.
Further we advise calling an experienced pool specialist to do maintenance. Always remember the heater is a gas appliance and never take a chance. We recommend having an annual health check. That’s because, just like kettles the heating chambers accumulate scale from the pool water, plus what the rain, sleet and snow add.
So How Much Does It Cost to Purchase a Pool Boiler?
We decided to take a grab sample from Amazon where we expected prices would be good. The first one that caught our eye was a 400,000 Btu ‘Pentair 460737 MasterTemp High Performance Eco-Friendly Pool Heater’ running on propane natural gas.
The advertisement claimed ‘best-in-class energy efficiency’ whatever that may be. The asking price was US$ 4,250 so around £3,200 at the time, quite expensive.
Our eye next fell on a ‘Zodiac LRZ125ENC Legacy Digital 125 BTU Natural Gas Bronze Headers Heater with ASME Certified Copper Tubes’. This was clearly destined for a hot tub and the price of $2,165 so £1,630 seemed high.
Then we noticed the small print ‘Manufacturer warranty will not apply. Please review Amazon’s return policy, which usually offers free returns within 30 days of receipt.’
We would personally never purchase a gas appliance on a website, unless this was a UK company with brick and mortar on the ground. Our recommendation would be to find a reputable installer with deep knowledge of gas in the swimming pool industry.