Last updated on June 20th, 2024 at 08:16 am
This piece was kindly contributed by Dave Roberts, UK MD at energy storage specialists GivEnergy.
GivEnergy is the UK’s best selling residential energy storage brand.
Heat pumps are on the rise.
Microgeneration Certification Service (MCS) figures show installations in UK homes are at record levels.
So too are installations of home battery storage systems, as more of us look to cut energy bills and carbon emissions.
So, you may ask the question, ‘Can I run a heat pump on a home battery?’
In this guide, Dave Roberts, UK MD at energy storage specialist GivEnergy brings you the answer.
Home battery basics
An increasing number of UK homeowners are opting for a home battery storage system.
This could be:
Battery storage coupled with solar PV panels
Generating energy from solar is a great way to reduce the amount of electricity you draw from the grid. Solar PV panels allow you to cut both your energy bills and carbon emissions.
However, without somewhere to store the energy generated from your solar array, a lot of that energy can go to waste.
Battery storage lets you store solar energy to use when you need it most, such as during peak hours.
Or…
Standalone battery storage
A good choice if you don’t have the means – practical, financial, or otherwise – to install solar panels.
A standalone battery storage system works well for those on smart time-of-use electricity tariffs.
Charge your battery from the grid during cheaper off-peak electricity hours, such as overnight. You can then use this energy to run your home during more expensive peak hours, helping you avoid more expensive electricity.
A standalone battery can not only cut your bills, but also reduce strain on the grid during peak hours.
Now the battery basics are out the way, let’s get to the question at hand.
So, can you run a heat pump on a home battery?
Short answer: yes.
Heat pumps require electricity to function. So, like any other electrical device in your home, a heat pump can run on electricity from a home battery.
In fact, due to the amount of electricity they use, it’s even recommended to combine solar PV panels, battery storage, and a heat pump. Research by the Fraunhofer Institute for Solar Systems in Germany shows that this very combination can improve heat pump efficiency and reduce reliance on the grid.
After all, isn’t the whole point of a heat pump to have sustainable heating that lowers your energy bills? A heat pump which draws a load of electricity from the grid is potentially neither green nor cost-effective.
That being said, there are a few questions you MUST answer if you plan on combining a heat pump with a home battery storage system.
Let’s delve into them one-by-one.
(Disclaimer: everybody’s energy needs differ, depending on a whole range of factors. We cannot tell you exactly how to set up your heat pump and home battery combination. We’re just here to give you a few pointers on what you need to pay attention to.)
1. How much electricity does your heat pump use?
Let’s assume you’re replacing a traditional gas boiler with a heat pump for all your heating needs.
You need to figure out how much electricity your heat pump will use to produce the equivalent amount of heat as your gas boiler.
To calculate this figure, you need to know something called the coefficient of performance (COP).
This is a number which tells you how many kilowatt hours (kWh) of heat is produced for each kWh of electricity consumed. In short, it tells you how efficiently your heat pump is working.
Imagine it’s a cold winter’s day and you need 38kWh of heat to keep your average-sized 2-3 bedroom home warm.
Your heat pump is operating at a COP of 3.3.
So, how much electricity does your heat pump use in this case?
You get 3.3kWh of heat for each kWh of electricity.
So, your heat pump would need around 11.5kWh of electricity to keep your home warm.
One more thing to note
Your heat pump’s COP can fluctuate, depending on a whole range of factors.
Contrary to popular myth, heat pumps work in cold weather. However, expect the COP to be lower when it’s colder. That means during colder weather, your heat pump will use more electricity for lower heat output.
To get a comprehensive picture of how much electricity your heat pump uses, make a rough calculation of how much heat you need during the coldest days of the year.
Once you’ve got this figured out, you’re on the right track to choosing a suitably sized home battery.
2. Does your home battery have enough capacity to run a heat pump?
Let’s assume you want your home battery storage capacity to cover most, if not all, of your household electricity needs – including the running of your heat pump.
To properly size a home battery, you need to consider the following.
Electricity usage in your home
Fortunately, figuring this out has never been easier.
With a smart meter, you can track your overall electricity usage. Meanwhile, for individual devices, you can monitor via a smart plug.
If you’re using high-powered devices – such as a hot tub, EV charger, etc. – this will inevitably increase your electricity usage.
Make sure to take into account any seasonal variations in electricity usage.
Added electricity usage of heat pump
If you’re installing a heat pump, this will cut down or even eliminate your gas usage, depending on your setup.
However, it will add to your electricity usage.
Be sure to take this into account when choosing a home battery.
As outlined above, make sure you get a rough figure of how much electricity your heat pump needs to heat your home during the coldest winter days.
You can then choose a home battery with enough capacity to cover most of, or all of this amount.
If you already have a home battery and want to install a heat pump…
… then it may be the case that you have to add extra battery storage capacity to accommodate your heat pump’s electricity usage.
Let’s say you’ve already got a good idea of your household electricity usage and have installed a home battery storage system to match.
Factor in how much extra electricity your heat pump will use, and then add battery storage, accordingly.
Fortunately, almost all home battery storage systems allow for retrofit options. So, you can add extra capacity to meet your needs.
3. How can you make your heat pump and home battery combination work more efficiently?
Here a few tips to make your heat pump run more efficiently:
- Avoid changing the set temperature – regularly turning it up or down means your heat pump will use more power.
- Check the water heating temperature – if it’s too high, your heat pump will use more electricity than necessary.
- Properly maintain your heat pump – pay attention to dirty or blocked filters.
To reduce overall electricity usage in your home, you can consider:
- Turning devices off which would normally be left on standby.
- Using energy efficient devices, such as LED lightbulbs.
- Closely monitoring your electricity usage via a smart meter and smart plugs.
More efficient electricity usage will ultimately lead to a more efficient heat pump and home battery combination.
That being said, these are all handy tips, regardless of whether you have a heat pump and home battery.
Caveats
A heat pump combined with a properly sized home battery can help you cut energy bills and carbon emissions.
This combination works even better if you add solar panels into the mix.
However, as with many things home battery-related, there are some things you just can’t predict!
- You can’t predict whether your energy needs may change in the future, especially if you add high-powered devices.
- You can’t predict exactly how efficiently your heat pump will work, especially during the coldest of winter days.
- If you have solar panels, you can’t predict how much solar energy you’ll produce from day to day.
- Even with a home battery, there will likely be days when you need to draw electricity from the grid to run your heat pump and other home devices.
Nonetheless, a heat pump and home battery combination is STILL worth it. That’s because at the very least, you can minimise how much electricity you draw from the grid.
Good for cutting your energy bills. Good for cutting your carbon emissions. And ultimately, good for the rest of us.
