The trouble with extensions

The trouble with extensions

When it comes to home extensions, heating may not always be front of mind for homeowners. From Building Regulations and heating zones through to identifying if an existing system can cope with the new heat demand, Jonathan Tedstone explores the topic and offers some helpful advice for installers.

Recent figures released by the Bank of England show that mortgage debt has lowered significantly, as many homeowners are opting to add value to a property with a range of improvements such as attic conversions, new kitchens and bedroom extensions. However, often the last thing a homeowner considers is how any extension will affect their home heating system, which can sometimes lead to confusion and complications.
Customers who have done their homework may have already researched what is available and could have some idea of how they would like to heat the extra space – including methods such as electric heating and underfloor heating.
However, the heating engineer has a major role in recommending what would work for them – based not only on the size of the extension but also a number of other factors including current heating system, condition of the boiler, budget, and even how often they will use the space.
When discussing these options, it is imperative to consider whether the home’s existing boiler is able to cope with the extra demand that goes with heating an extension. If the boiler is fairly modern, high efficiency and has capacity, this is often the most straightforward way of heating the extension with minimal cost.
In the case of a loft conversion or extended kitchen, it may be simply a case of installing new radiators. For larger or more complex projects, however, electric underfloor heating can be a practical way of heating a new space. On some occasions, it may require a new boiler entirely – a cost perhaps not considered by the homeowner.
Extensions can sometimes mean that a boiler has to be moved, particularly when the customer has chosen to extend a kitchen or utility room. However, it is not simply a case of picking it up and moving it; in fact, under current Building Regulations, this is classed as a new installation.
Therefore, the customer will need to install a high efficiency boiler in order to meet these regulations, which you will need to explain to the homeowner. This can add time, and cost, to the overall extension, which needs to be factored in.
Any work carried out to the heating system must comply with Part L of the Building Regulations.  Independent temperature and on/off controls are a requirement of Part L. TRVs and a room thermostat should be installed to help regulate the temperature and maintain comfort in the home.
While the addition of TRVs may be viewed as the norm in a new installation, many existing houses are still without. Depending on the size of the property, heating zones may also be required.  If a property is larger than 150 square metres, it should be divided into at least two heating zones for greater comfort levels and to increase efficiencies. For example, a temperature of around 21°C may be required in the downstairs living areas, while a cooler 18° C may be more comfortable in the bedrooms.
In fact, Part L details a minimum standard of control; this will include TVRs, room thermostat and a timer for use with a combi boiler, and the addition of a cylinder thermostat and one two-port motorised valve when a system or heat only boiler is installed. These must be wired so that they are interlocked with the boiler and pump in order to prevent the boiler from firing when there is no demand for heat. Though this guidance is mostly aimed at new-build dwellings, they also apply every time a home has an extension or change of use.
Importantly, the onus is on the installer to ensure that their customers’ properties meet the requirements of Part L, and that they explain to them how using the controls correctly will improve the overall efficiency of the domestic heating system.
When your customers are planning an extension, it is important to discuss all their options with them first, before building work even commences.
For example, if they are considering underfloor heating, explain that it must be planned in and installed before the floor has been laid.
Also, if they are considering the possible installation of solar thermal panels at a later date, they can future-proof the installation by fitting a solar cylinder and any necessary pipework. Even when using a conventional boiler, the cost of installing a new one could be a shock if it hadn’t been considered.
It is always useful to have discussions with the building contractor, so that all parties are working together. Heating needs to be seen as an integral part of the build rather than an afterthought. That way, the extension is as straightforward as possible for your customer – and you.