Worried in case a higher kW boiler costs more to run?
You’re not the only one. But the good news is, you don’t have to!
You see, a lot of people err on the side of caution and will fit a larger output boiler to ensure they won’t feel the cold in the depths of winter. Usually what happens next, is that their other half will start to worry and ask: “Is that not a bit like running around town in a gas-guzzling car, burning more fuel than you need?”
As an engineer with over 20 years’ experience in the heating industry, let me take the time to reassure you that this is not the case.
Will a higher kW boiler ever cost more to run?
The short answers is no. All modern boilers are fully modulating, so this is no longer an issue.
Older boilers used to cut on and off on a cycle, wasting gas. Modern boilers will fire up on a high flame, and as radiators or water reaches temperature, they’ll reduce the size of the flame (modulating), then stay simmering so they aren’t wasting gas.
Due to the higher output, they can heat your home faster, but then go into simmer mode, whereas a smaller boiler will stay on high fire longer to get the radiators to temperature.
Your chosen heating engineer should be able to work out the correct output you need for your home.
How is this worked out by an engineer?
Any reputable heating engineer should be able to measure your home’s heat loss, and figure out the correct output for your home by taking into account the number of radiators on the system – plus if you have a system or regular boiler, the capacity of hot water necessary.
They should also take into account things like insulation, the height of your ceilings, and the number of outside walls. All of this affects the heat needed, and your home’s heat loss.
But not all engineers are right. I once had a customer who wanted a 38kW combi boiler (with 30kW to the heating) as she had a rain shower. This is what another engineer told her what she needed. I quoted on a 36kW boiler (with 24kW to the heating – as she only had six radiators).
As a result, I didn’t get the job – however, I did give her the best advice. And I won’t fit a boiler that’s unnecessary, just because a customer wants me to.
Advice from an experienced engineer
Always get 2 – 3 fixed price quotes so you can compare what different engineers are saying. And remember, you can err on the side of caution, but there’s no point in going over the top. The biggest issue I have is with combi boilers, where engineers give people a combi with a heat output of 30kW to the radiators when they only have four or five to heat.
So, although the boiler modulates, you’re still paying £200 – £300 more for a higher specification boiler that you don’t need.
If possible, always do your research, and look up about energy efficiency and waste online. Ask the questions to your engineer about the best-sized boiler for your property – including what’s best for efficiency as well as cost.
Conclusion
Thanks for reading. Hopefully this blog post clears up the misunderstanding that a higher kW boiler costs more to run. These days boilers are self-modulating, so you shouldn’t run into that problem. It may be wise to err on the side of caution, but any reputable engineer will not fit a boiler that’s far too big for your needs.
Got a question about higher kW boilers that I haven’t answered yet? Let me know in the comments’ below. I’ll be happy to reply!
