Do You Need a Hot Water Cylinder With a Heat Pump?

Q: Can I keep my existing hot water cylinder with a heat pump?

Sometimes, but often not. A heat pump needs a cylinder with a larger coil to transfer heat efficiently, and many older tanks do not have one. We inspect yours at the free survey and tell you honestly whether it can stay or should be replaced.

Q: Can I fit a heat pump if I have a combi boiler and no space for a cylinder?

Usually yes. A cylinder can often fit in a cupboard of at least 80cm x 80cm (Energy Saving Trust, 2026). If space is tight, we look at alternative spots such as a utility room or loft during the survey, and explain the options before you decide.

Q: Does a heat pump cylinder mean I will run out of hot water?

Not if it is sized properly. The cylinder is chosen for the number of people and bathrooms in your home, so there is enough stored for normal use. We set the size at the survey and write it into your quote.

Do you need a hot water cylinder with a heat pump? Learn why, how much space it takes and what to expect from Hot Water Cylinder Installation in Walsall.

Last updated: October 2026

Yes, in almost every case you do. If you are thinking of swapping your boiler for a heat pump, the question of where your hot water will come from matters as much as the radiators. At Eco Air Source Heat Pump Installer, a Walsall-based firm, we get asked about it on most surveys. A heat pump heats water gently and steadily, so it needs a hot water cylinder to store it. This guide explains why, what fits where, and what to expect, so you can plan a hot water cylinder installation without surprises.

Call 01922 302461 any day, 9am to 7pm, if you would rather talk it through.

Why a heat pump needs somewhere to store hot water

A heat pump cannot heat water on demand the way a combi boiler does. It warms water slowly at a lower temperature, so the hot water has to be stored in a cylinder, ready for when you turn on a tap or run a bath.

That means a combi boiler setup, with no tank at all, does not carry over. If your home currently has no cylinder, one will need to go in. If you already have a cylinder, it may not be suitable, because heat pumps need a cylinder with a larger internal coil to transfer heat properly. Older cylinders are often not built for this, so we check yours at the free home survey and tell you plainly whether it can stay.

Where does the cylinder go, and how much space is needed?

A hot water cylinder can usually fit in any cupboard that measures at least 80cm x 80cm (Energy Saving Trust, 2026). Many homes in Walsall already have an airing cupboard or a spot in a utility room or loft that works.

Things we look at when choosing the spot:

Floor strength and height: a full cylinder is heavy, and the ceiling must clear the tank and its pipework.
Distance from the heat pump: shorter pipe runs mean less heat lost along the way.
Access: the cylinder needs to be reachable for servicing.
Size: the right capacity depends on how many people live in the house and how many bathrooms you use.

If you currently have a combi boiler, the space the boiler and any old tanks took up often helps. We will measure on the day and put the position on your written quote, so you know before committing.

Will it cost more, and what does it do to running costs?

The cylinder is normally included in the price of the full system, not added as a surprise extra. Installed heat pump costs vary by source: around £12,000 typically (Energy Saving Trust, 2026), £8,000 to £14,000+ (Renewable Energy Hub, 4 Aug 2026), or £5,000 to £15,000 (Worcester Bosch, seen Oct 2026). Your figure depends on your home, the cylinder size and whether radiators need changing.

On running costs, electricity is nearly four times more expensive than gas on standard tariffs, so a heat pump can cost slightly more to run than a new gas or oil boiler. A heat pump time-of-use tariff can bring running costs below a gas boiler (Energy Saving Trust, 2026). A cylinder helps here, because it can be heated when electricity is cheaper and the hot water used later.

Grants and the cylinder

Homes in England and Wales can get £7,500 towards an air source heat pump through the Boiler Upgrade Scheme (Energy Saving Trust, 2026). You must own the property and be replacing a fossil fuel system such as oil, gas, electric or LPG (GOV.UK, 2026). The grant comes through our MCS-certified partner, who quotes, installs and applies on your behalf. If you do not need the grant, we install the heat pump ourselves.

Key takeaways

A heat pump stores its hot water, so a cylinder is needed in nearly every home.
An old cylinder may not suit a heat pump, so it should be checked.
A cupboard of at least 80cm x 80cm usually works (Energy Saving Trust, 2026).
Heating water at cheaper tariff times can help keep running costs down.
The Boiler Upgrade Scheme grant comes through our MCS-certified partner.

Next step

Want to know what a cylinder would involve in your home? Our Hot Water Cylinder Installation page explains the work in more detail. Call 01922 302461 or request a free survey. You can also visit us in Walsall, WS1.