How do we revamp our heating system?
Query: We have recently bought a three-bedroom mid-terrace house built circa 1900 and have been told we need to replace the current heating system. What are the most economic options available to us in terms of installation and running costs? I've heard a lot about heat pumps recently and was wondering if this could be a good option?
Answer: Since April 2018 a new grant has been available for heat pumps from the Sustainable Energy Authority of Ireland (SEAI). Heat pumps are electrical devices that extract the heat from a specific source - either air, ground or water - and convert it into usable heat.
They can be a very effective way of heating your home, but their efficiency relies on ensuring adequate insulation to minimise heat loss. This is relatively easy to realise in a new build by insulating the building to a high standard, however in an existing property it can be prohibitively expensive.
Types of Heat Pumps
There are two different types of heat pumps commonly used in domestic heating which are distinguished by their sources:
Ground-to-water heat pumps use the earth as a source. These are very efficient and are more commonly used in new builds where they employ underground piping to source heat.
Air-to-water heat pumps are most common in retrofit projects as they are generally the easiest and cheapest to install, requiring an externally-mounted unit to collect heat from the air outside your house.
While these systems work efficiently with underfloor heating, another option is to oversize the radiators by around 35pc to take full advantage of lower operating temperatures.
Regardless of which source of heating is used - whether it's alternative energy or fuel - the pipes and the radiators will be the same. A heat pump can be retrofitted onto an existing traditional system and will work with conventional radiators in most cases.
Avoid Heat Loss
If you are considering a heat pump system, it would be advisable to have a technical assessment carried out to determine the level of heat loss your home experiences and to identify ways to reduce that heat loss.
Upgrading the windows or insulating your new house either internally, by dry-lining the walls or insulating the attic, or externally, through thermally-insulated exterior cladding, are all means to achieve this. This assessment is compulsory if you are considering applying for an SEAI grant.
Any alternative energy source system will have a higher initial outlay to supply and fit, which is offset over a period of time through reduced heating costs. It is important to note that many factors, such as the fabric, age and size of the house, will influence whether this will be the most cost-effective option for you. A registered architect will be able to advise you on the best option for your home.
What are the other options?
If natural gas is on site, a high-efficiency combination gas boiler could be the way to go as it cuts down on installation costs and running costs. This compact unit functions as both a water heater and a central heating boiler and, as it does not require a hot water cylinder, it also saves space, making it a practical option for smaller properties.
An oil boiler is more expensive and you would need to accommodate the oil storage tank somewhere on your property in compliance with fire separation distances set out in the OFTEC guidelines.
For more information on grants, see seai.ie/homeenergygrants.
- If you are considering changes to your home, work with a registered architect. Check riai.ie, the registration body for architects in Ireland for one near you.
- Ciara McGonigal is a registered architect in private practice; studioand.ie
Do you have a design dilemma we can help you with? Email firstname.lastname@example.org. Advice provided is for guidance only and readers are advised to seek professional assistance for any proposed project.