Guide to Radiators: Choose the Right Size and BTU Rating

A guide to radiators: how to choose the right size and why BTUs matter

It's important that every room in your house has the appropriate size radiator when installing or replacing existing ones. A weak radiator won't be able to heat the space sufficiently, but an overly large radiator would not only overheat the space but also cost you more money to operate. BTUs are used to measure the size, or power, of a radiator.

BTU: what is it?

BTU stands for British Thermal Unit. This indicates the maximum amount of heat a radiator can emit. To heat a pint of water by one degree, one BTU of energy is required. The radiator's ability to heat the area surrounding it will increase with BTU count.

The typical BTU output range for central heating radiators is 600–10,000.

Factors to consider when choosing a radiator

There are a few crucial factors to take into account when choosing the best radiators for your house.

What is the room's size?

It's critical to understand the size of the space that the radiator must heat. This information must be given in square metres.

How many windows do you have?

You must factor in all windows as potential sources of draught when doing your calculations.

What's on the other side of the wall, above, or below it?

Unlike those installed above cellars or against cavity walls, radiators on solid floors, against solid walls, or beneath well-insulated ceilings won't need to work as hard. Account for nearby unheated spaces when calculating BTU requirements.

Alternatives to radiators

Your options are not limited to radiators. These "hidden" heating alternatives can also help you make more room in your house.

Underfloor heating

In place of radiators, underfloor heating is the most common substitute. Installing underfloor heating is a much larger task than installing radiators, as you might anticipate. Additionally, it works best when adding to or renovating an addition, so you can wave goodbye to concerns about furniture getting in the way of radiators.

If you are exploring underfloor solutions, our underfloor heating service can advise on whether it's suitable for your home and how it will integrate with your existing system: underfloor heating.

Speak with qualified heating engineers

Sizing radiators correctly avoids unnecessary comfort issues and running costs. For a reliable, efficient outcome, speak with qualified heating engineers who can assess heat loss, room usage and building construction and recommend the correct radiator sizes or alternative heating systems.

We are available throughout West Sussex and Hampshire — simply get in touch by calling us on 07391473964, or take a look at our heating design service: heating design.