Owning and operating a heat pump – one year on
In summer 2024 we replaced a 20-year-old oil boiler with a heat pump. Our initial impression post installation was positive. But what’s it like just over one year later, during our second heating season?
In one word – great.
Our main expectations, aside from the obvious environmental benefits, were steady, even comfort through the heating season, constant hot water, and, hopefully, reduced running costs. And we aren’t disappointed.
Running Costs
Let’s deal with running costs first as it tends to be most people’s first question or consideration. When we upgraded our 200 square meter bungalow (with cavity wall insulation, two high performance outer doors, a stove replacing an open fire, and a heat pump), we went from a C3 to an A3 rating. In our first full heating season (September 2024 to May 2025) our electricity costs to run the heat pump were around €1,300 which was around €250 lower than we spent on oil the previous year. And, as you’ll see below, our house is just so much more comfortable.
Steady Comfort
One of the big promises of a heat pump is the steady, warmth throughout the house. You see, a heat pump heats the water circulated through your radiators to a lower temperature than a conventional boiler. So, instead of blasting heat into the house periodically, causing the temperature to go up and down, it trickles heat in to keep the temperature constant.
So, what does that feel like? Well, the first thing you notice is that the radiators never get hot in the way we’re used to – they vary from lukewarm to warm. But the house is simply nice and cosy ALL the time, hovering around 20C in every room; we’re comfortable in our home morning noon and night and spending less money on heat than we used to. Once it is turned on and running for the winter, that’s it, we don’t have to think about timers or anything, we just let the heat pump do its job.
We have three thermostats in the house. They are only there to prevent overheating, which could happen for example on the days when there is very low and intense sun at the front of the house. This tends to turn off one zone while the others keep trickling away.
And visitors to the house notice it too, commenting that they always know when they arrive at our house that it will be lovely and comfortable all the time and in all rooms.
So coupled with our lower running costs, what I can honestly say is that our home is twice as comfortable as it ever was, and it is now costing us less to heat.
A heat pump’s superpower is what’s called weather compensation. In a nutshell, the heat pump adjusts the temperature in your radiators depending on the weather outside so that the temperature inside stays the same. It means rads will be only barely warm on milder days and very warm on those Baltic days - and everything in between – but the temperature in your home will stay the same This will mean lovely steady comfort inside, whatever the weather, and the heat pump is always operating at optimum efficiency, saving you money.
Constant Hot Water
Yes, this is a thing. Twice a day, the heat pump does a short 30–40-minute cycle where it also heats the 210-litre cylinder to a toasty 53C. You might think this seems low because your current immersion heats to 60C which is actually a lot hotter than you need, you always add cold water to the mixer tap or shower.
So, there is always plenty of hot water, even when we have high demand, like the kids staying overnight and everyone showering in the morning. And in those situations, the intelligent controls will spot high usage and when the cylinder drops below a reasonable volume of hot water it will compensate. The cylinder is super-insulated, so if we don’t use much of the water, it barely takes any energy to top it up.
By the way, the reason your old immersion heats to 60C is because occasionally your cylinder needs to hit that temperature to protect against harmful bacteria in your cylinder. But your immersion only knows one temperature, so it uses it all the time, which is very wasteful. The heat pump on the other hand does one short cycle at 60C once a week, which is more than sufficient.
All highly intelligent and efficient.
Best of all, since July of last year, I haven’t once had to think about the immersion switch being on or off, or whether it was set to sink or bath. Pure bliss.
If you would like to see a little bit more of our heat pump set up, check out our heat pump explainer video below which was shot at our house with my expert colleague Brian McIntyre doing the explaining.
