Can You Use AGA for Underfloor Heating?

Yes, you can use an AGA for underfloor heating, but it requires a thermal store system to work properly. Traditional AGAs produce continuous heat that can be captured and distributed through underfloor pipes, though modern controllable models offer more straightforward integration options.

We've removed hundreds of AGAs over the years, and many homeowners ask about heating options before deciding whether to keep or replace their cooker. The reality is more complex than a simple yes or no.

How Does AGA Underfloor Heating Work?

Traditional AGAs generate constant heat, which makes them natural candidates for water heating. A thermal store acts as the middleman between your AGA and the underfloor heating system. Hot water from the AGA's boiler circulates through a coil inside the thermal store, transferring heat to the stored water without mixing the two systems.

This stored hot water then feeds your underfloor heating circuits at the right temperature. Think of it as a giant hot water battery that smooths out the AGA's heat output and delivers it where needed.

The system needs proper controls to manage water temperature, as underfloor heating typically runs at 35-45°C, much cooler than radiators.

What Equipment Do You Need?

Converting an AGA to power underfloor heating requires specific kit beyond just pipes and manifolds. The thermal store is your biggest investment, typically a 200-300 litre insulated cylinder with internal coils.

You'll need a mixing valve to blend hot and cold water to the right temperature for your floors. Underfloor heating can't handle the full heat from an AGA boiler directly.

Essential components:

• Thermal store cylinder (200-300L capacity)

• Mixing valve and temperature controls

• Circulation pumps (usually two)

• Zone valves if running multiple areas

• Expansion vessel and safety valves

• Insulated pipework throughout

Your AGA must have a boiler fitted. Not all models do. Rayburns typically come with more powerful boilers than AGAs, making them better suited to whole-house heating. If you're choosing between fuel types, note that converting a gas AGA to solid fuel might give you more heating capacity.

Installation Costs and Considerations

Expect to pay £3,000-£6,000 for a professional thermal store installation, not including the underfloor heating itself. The thermal store alone costs £1,500-£2,500, and you need an experienced heating engineer familiar with both AGAs and thermal stores.

A standard plumber won't do. These systems require careful balancing and commissioning. Get it wrong and you'll have cold floors, an overheating AGA, or worse.

Factor in annual servicing costs too. Thermal stores need checking, and the whole system is more complex than a standard boiler setup. We've seen poorly maintained systems fail after just five years.

Traditional AGAs vs Modern Controllable Models

Traditional AGAs run constantly, making them reasonable heat sources for underfloor systems. But they're inflexible. When you don't need heating in summer, that AGA keeps pumping out heat. Many owners find AGAs expensive to run partly because of this always-on nature.

Modern controllable AGAs work differently. Models like the AGA eR7 or AGA Dual Control can be programmed to heat only when needed. Some have dedicated boiler units that operate independently from the ovens.

These newer units often connect to underfloor heating more simply, sometimes directly through a conventional heating system without needing a thermal store. If you're considering converting a gas AGA to electric, the latest electric models offer the most control.

When It Makes Sense (And When It Doesn't)

Using your AGA for underfloor heating works best in specific situations. Open-plan kitchens benefit most, as the heat source and the heated floor are in the same space. Small extensions or conservatories adjoining the kitchen also make good candidates.

It rarely makes sense for whole-house underfloor heating. AGAs aren't designed as primary heating sources, despite heating the house to some degree. A dedicated boiler costs less to install and run.

Consider your long-term plans too. If you're thinking of selling, remember that second-hand AGA values depend partly on condition and specification. Complex heating setups can put off buyers who just want a simple cooker.

Common Problems and Solutions

Thermal stores can develop issues that affect your underfloor heating performance. Scaling inside the coils reduces heat transfer, especially in hard water areas. Annual descaling helps, but it's another maintenance task.

Pump failures are surprisingly common. The circulation pump works hard, running whenever the AGA's hot. Keep a spare pump handy or face cold floors in winter.

Temperature creep is another issue. Underfloor heating works best at steady, low temperatures. AGAs produce variable heat depending on use. Your mixing valve must constantly adjust, and cheap ones struggle with this.

Some installations suffer from gravity circulation, where hot water moves through the system even when pumps are off. This wastes energy and can overheat floors. Proper pipe routing and check valves prevent this.

Alternative Options to Consider

Before committing to AGA-powered underfloor heating, consider simpler alternatives. A separate system boiler gives you full control over heating times and temperatures without affecting your cooking.

Electric underfloor heating mats work well in kitchens and bathrooms. They're cheaper to install and completely independent of your AGA. Running costs are higher, but the simplicity often wins.

If you specifically want the AGA aesthetic but better heating control, look at companion boilers. These match your AGA's appearance but operate independently. Williams makes units designed to sit alongside AGAs.

Some homeowners switch from AGA to a modern range cooker with better efficiency. You lose the traditional charm but gain flexibility. We handle plenty of AGA removals where owners upgrade to more controllable cooking and heating systems.

Remember that AGAs need special pans and cooking techniques. If you're already adapting your entire heating system around the cooker, make sure you actually enjoy cooking on it first.