How to write a brief for a renewable heat system
Posted by Tasha Kosviner on 22 January 2014 at 9:05 am
Once you have decided that you’d like to install a renewable heating system in your home or office, it’s a good idea to write a brief for the project. Rather than detailing all the various technologies you’ll need, a brief is designed to set out your expectations and can be a benchmark against which the success of your project is measured.
Installers can use the brief to provide you with their recommendations and, eventually, a quote and it will help you when evaluating different quotes and working out which best suits your needs.
1. Outline of your project
Use this space to include details such as whether your project is domestic or commercial, whether it’s new build or a retrofit. Include what you’d like to achieve with your installation, for example heating a three-bedroom house, heating a swimming pool, generating electricity and so on and what system, if any, is being replaced.
You may choose not to share this information with potential contractors for the purposes of the quote but you should have an idea of how much it will cost before you start looking for quotes. Use the first table below to work out roughly what sized system you’ll need according to the age and floor area of your house, and see the second table to give you an idea of the average cost of a 10kW system.
3. Energy efficiency standards
Your local planning authority will be able to tell you what minimum standards you need to meet. For new builds, these will probably include Part L for the conservation of heat and power in domestic buildings or the SBEN/BREEAM Standard for commercial buildings. Other more stringent standards you may wish a new build to meet include the Code for Sustainable Homes and the Passive Haus Standard.
4. Planning restrictions
In addition to the energy efficiency standards noted above, make a note of any planning restrictions that may apply to your project, for example if the building is listed or lies within a conservation area. If you are looking at water source heat pump, use this space to note what permission has been sought from the environment agency.
5. Return on investment
Newly installed renewable heating systems will qualify for renewable heat premium payments and/or the renewable heat initiative (RHI), providing they meet certain standards. If you'd like to receive these payments, and why wouldn't you, then make sure that you stipulate that your installation must be made by an MCS-approved installer and that your whole property must be adequately insulated. Your insulation will need to be checked by an assessor as part of the RHI application process, as will your MCS certification and you will not qualify if the necessary standards are not met. If your installer is not aware of these standards you may not consider them the right company for the job.
6. Site restrictions
The type of system you settle on could well be dictated by the geography of your site. Biomass boilers, even on a domestic scale, require a large dedicated shed for fuel storage with space for deliveries. Ground source heat pumps will require digging up land to install a ground loop connector (as a guide, you will attain 25W per square metre and up to 50W per lineal metre of bore hole) while air source heat pumps have a relatively small footprint and are easy to install. However, they tend to produce slightly more noise than ground source machines so it is worth considering the position of the outdoor unit to minimise noise disruption. When it comes to solar thermal (for heat and hot water, as opposed to solar electricity) you will need at least five square metres of un-shaded south facing roof to make any significant contribution to hot water production.
7. Performance requirements
Make a note of how you currently heat your house, for example whether it’s on all day or only in the mornings and evenings, and whether you’re prepared to be flexible with this pattern to attain a more efficient system. For example, most heat pumps run more efficiently if they are on all the time, at a lower temperature. You may also need to decide whether you can use your existing radiators or go to the expense of installing larger ones which will run more efficiently with a heat pump.
8. Extra controls
Finally you should look at how you’d like to control your system. Zoned thermostats that allow you to control the temperature in each room, or on each floor, independently are useful, while a system that allows you to set different flow temperatures at different times of the day could be useful too. Some manufacturers, such as Stiebel Eltron, have a range of heat pumps that incorporate an internet service gateway to allow remote tracking of performance, system control and can automatically contact your service engineer if it detects a fault.
This article is based on a guide produced by John Felgate of Stiebel Eltron, who is the Chairman of the Domestic Heat Pump Association. You can download the more detailed version here.
If you have a question about anything in the above blog, please ask it in the comments section below.
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