Things to Consider before Replacing your Old Boiler

Among the more significant, and consequential, upgrades you can make to your home is the installation of a new boiler. Depending on how old and rickety the existing boiler is, you might enjoy a substantial improvement in efficiency, noise and capability. With that said, the outlay is going to be a significant one, and thus you’ll want to bear in mind a few important factors.

What type of boiler is it?

Boilers come in two varieties. There are gas boilers, and there are electric ones. The former is typically less expensive than the latter, but since gas is much cheaper than electricity, this advantage isn’t really an advantage in practice.

Most modern boilers are combi boilers. These don’t require any extra storage tanks for the water being heated; they instead include a small tank within the enclosure, and heat up the water you’re using on demand. For larger households (and public buildings), a conventional boiler with separate storage tanks might be preferable. A system boiler is a little bit like this, except that it doesn’t have a cold-water storage tank – it gets cold water straight from the mains. In conclusion, remember that the type of boiler you might need will change according to the type of house you have. The larger or smaller it gets, the options then vary. To assess the right one, you can follow the advice given on

How big is it?

The size of your boiler should be proportional to the amount of water it’s expected to heat. Too big, and you’re wasting money; too small, and you’re stressing out the boiler and thereby shortening its lifespan. Bear in mind also the space you’ll require to accommodate the appliance; big boilers take up more room.


Measuring boiler efficiency is something that impartial reviewers should be able to do. Today, all modern boilers come with lettered ratings from the European Union, but you might still refer to the SAP hot water efficiency rating, which measures how quickly the boiler can get to temperature. The faster the boiler, the less water (and time) you’ll be wasting.

Modulating Boiler Controls

Traditionally, boilers are either on or they’re off. They bring the water to a given temperature and then they shut off. Modulating boilers controls allow a boiler to instead provide a constant level of heat. This means greater efficiency, and greater comfort while you’re at home. In order to take advantage of this, you’ll need a thermostat and a boiler that can communicate with one another through the Opentherm standard, or a proprietary alternative. 

Often, this means matching the thermostat to the boiler manufacturer. If you have a Worcester Bosch boiler, for example, then you’ll need a Worcester Bosch thermostat.

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