Buying Guides
Regular (Heat-Only) Boilers Explained
Reviewed by our Gas Safe registered engineers · Last updated 22 July 2026
Regular boilers — also called heat-only or conventional — use a hot-water cylinder plus tanks in the loft. They’re the traditional setup in older homes. Here’s how they work, when to keep one, and when to convert.
Quick answer: A regular (heat-only) boiler works with a hot-water cylinder in the airing cupboard and two tanks in the loft — a cold-water storage tank and a small feed-and-expansion tank. It’s the traditional system in older houses. Its strengths are excellent hot-water flow to many outlets and working well with low mains pressure; the downsides are the space the tanks take up and heat lost from stored water. Many homeowners keep a regular boiler when replacing like-for-like, but some convert to a system or combi to reclaim the loft.
At a Glance
What to expect from a regular boiler
How a heat-only system behaves, so you can weigh keeping it against converting.
| Aspect | What to expect |
|---|---|
| Hot water | Stored in a cylinder, fed from a loft tank — great flow to many taps |
| Space needed | A cylinder plus two loft tanks |
| Best suited to | Older homes, low mains pressure, several bathrooms |
| Water flow | Strong even where mains pressure is poor |
| Install cost | Like-for-like is straightforward; converting costs more |
| Heat loss | Some heat lost from stored hot water and pipework |
Pros & Cons
The upsides and trade-offs
The upsides
Superb hot-water flow to lots of outlets, works even where mains pressure is low, and a like-for-like replacement is simple because the tanks and cylinder stay. Well suited to larger older homes.
The trade-offs
The loft tanks and cylinder take up space, stored hot water loses some heat, and it’s a more dated setup. If you want to free up the loft or airing cupboard, a system or combi conversion may appeal — but that’s more work.
Engineer Insight
Keep it or convert?
If you already have a healthy regular system and low mains pressure, replacing it like-for-like is often the sensible, cost-effective choice — don’t let anyone talk you into a combi you don’t need. Where a conversion makes sense is when you want the loft space back, your mains pressure is good, and your hot-water demand is modest. We’ll check your mains flow rate first, because that’s what decides whether a combi or system boiler can actually deliver what your household needs.
Costs
What a regular boiler costs
Typical North London guide prices — you’ll always get an upfront quote before any work starts.
FAQs
Regular boilers — your questions answered
What is a regular (heat-only) boiler?
A traditional boiler that heats a hot-water cylinder and uses two tanks in the loft — a cold storage tank and a feed-and-expansion tank. It’s the classic setup in many older homes.
What’s the difference between a regular and a system boiler?
Both use a hot-water cylinder, but a regular boiler also needs loft tanks, while a system boiler has those components built in and needs no loft tanks. System boilers are the more modern version.
Should I replace my regular boiler with a combi?
Not always. If your mains pressure is low or you have high simultaneous hot-water demand, a regular or system boiler serves you better. If your mains pressure is good and demand is modest, a combi frees up space.
How much does a regular boiler cost?
A like-for-like regular boiler swap is typically £1,900–£3,200 fitted. Converting to a system or combi costs more because tanks and pipework have to change.
Are regular boilers being phased out?
Not banned, but they’re a declining choice for new installs — most replacements are system or combi. Parts remain available, and a like-for-like swap is still perfectly valid where the setup suits the home.
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