In this article, our Head of Operations, Max, answers all the questions our customers have sent in about air source heat pumps.

How much does a heat pump cost to run for the average household?

The amount your heat pump might cost to run will vary from household to household – depending on how warm you like your home, its size and the heat loss it experiences.

However, if you were to use your new heating system in exactly the same way as you were using a modern gas boiler, you would need to have a year-round average efficiency of about 280% to break even on costs (as electricity is currently more expensive than gas).

When designing your system, we aim to achieve a year-round average efficiency of 300% – 350%.

Personally, since I have replaced my old gas boiler with a heat pump, I have saved about a third on my energy costs, and I have my home warmer now.

Max Waddingham, Head of Operations at Good Energy

Find out more about heat pump efficiency and how much money you might expect to save in this article.

Are heat pumps suitable for older homes?

Heat pumps are suitable for all different types of home. We regularly install heat pumps in period properties, mid-century properties and much newer homes too.

Just like with any other type of heating system, insulation will reduce heat loss and keep your heat pump working efficiently.

Hear from one of our customers, Gabrielle, who had a heat pump installed at her 18th century home.

Does a heat pump give a similar result to a gas boiler?

If you choose to install a heat pump, you will find the end result similar to a gas boiler

Like a boiler, it will heat up your radiators and provide hot water and you can control your home’s temperature on a thermostat. There are subtle differences however – a heat pump will provide a lower level of heat consistently throughout the day, whereas lots of homes use boilers to provide shorter blasts of heat at certain times, then turn the heating off.

How do heat pumps work in cold weather?
Heat Pump Mythbuster

The refrigerant inside a heat pump unit is a gas that has a boiling point of -52 degrees C. This means that in any temperature above this point, the gas will be able to expand and take on heat energy from the air. We recommend that our heat pumps will keep your home warm in temperatures down to -15 degrees C. 

Why might my radiators need replacing?

Boilers and heat pumps heat your home in a slightly different way. Boilers provide short blasts of heat through your radiators at set periods throughout the day at a flow temperature of between 50 degrees and 70 degrees. Heat pumps provide a more gentle warmth and emit heat for longer periods throughout the day at a lower flow temperature between 35 degrees and 55 degrees. The lower flow temperature helps heat pumps to run at their most efficient.

However, when the temperature is lower, your radiators will need a bigger surface area to transfer the same amount of heat to your home – and this is why some of your radiators may need replacing. Another consideration is that radiators are often designed to fit underneath windows, so they may not be correctly sized for the room, or in the best place to heat it.

Before you get a heat pump, a home survey will assess whether the placement, number or size of your radiators should be changed to make sure your home reaches your desired level of warmth and comfort.

Why do I need a hot water cylinder and what does it do?

You might be used to living in a home with a combi boiler – which means that you don’t have a hot water tank as your water is currently heated up on demand. While this saves space, they can be quite inefficient and prone to breaking.

Heat pumps can’t heat up hot water on demand like a combi boiler, so they require a hot water cylinder.  A cylinder stores heated water so it’s ready to use when you need it. Heat-pump-ready cylinders have a large heating coil, so the lower level of heat provided by your heat pump has a large surface area with which to heat your water. They are very efficient and maintain their temperature well over many days.

In a busy family household, your hot water cylinder should provide more than enough water for your daily usage, even with multiple baths and showers.  But if you do run out, the cylinder will only take around 20 – 30 minutes to heat up again.

Do I need to worry about bacteria in my hot water cylinder?

In line with HSE guidelines, we will schedule your hot water cylinder to heat to 60 degrees C once a week to ensure your hot water remains free from bacteria. The rest of the week, it is most efficient to store your hot water at around 50 degrees. As a safe shower water temperature is around 36-38 degrees, this is more than hot enough.

How long does it take from quote to install?

On average, we will install your new heating system within one to two months after you reach out for a quote. This gives us time to carry out a home survey and schedule the installation around your availability, and it gives you time to think about what you want from your heating system.

However, if you do have tighter timeframes in mind, it is possible for us to install your system more quickly – please do make this clear when you get in touch.

How long does installation take and what level of disturbance should I expect?

On average, a heat pump installation will take five days, and will involve a team of three heating engineers and electricians working in your home. Installations can take longer if you don’t already have a wet heating system, or if we need to install substantial new pipework, but you will be made aware of this ahead of time.

If your installation takes place over the winter, our team will provide you with heaters to keep you comfortable. We can also plan to install your hot water cylinder on day two so that you can access the immersion heater.

How often do heat pumps go wrong?

Heat pumps are generally more reliable than a gas boiler, particularly combi boilers. However, like with any appliance, they do sometimes go wrong. That’s why we provide our customers with the peace of mind of our 10 year parts warranty.

We also provide remote monitoring and diagnostics. This means we will be able to check fault codes and possibly make changes that will get your heat pump working again without a call out.

Got more questions? Please have a look at our complete list of FAQs.

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