Heat Pumps for homes: retrofit or new build we have you covered
Although more typically thought of in new build contexts, heat pumps are an option for all types of building. The key is designing the right heat pump system for the individual project; whether that be an historic mansion or a semi-detached villa or a brand new passive house with triple glazed windows.
In this article we will briefly look at the different requirements that each type of home has and the different challenges they present when designing a central heating system using a heat pump.
Improving the carbon footprint of older buildings with heat pumps
Using renewable solutions for older buildings is an area of expertise for Stiebel Eltron UK. We pride ourselves on being able to offer customised solutions that work to save money and energy, whilst ensuring comfort.
Older properties have huge financial and practical incentives to seek alternatives to fossil and solid fuels. Not least among the incentives are the generous funding schemes available to refurbishment projects choosing a green heating option such as the boiler upgrade scheme.
We have a wide range of products eligible for government funding schemes and many that are specially designed for retrofit applications to overcome typical issues faced in these situations.
Will a heat pump work in an old house?
One of the most frequent questions we are asked is about heat pump systems for older homes is: how well insulated does a house need to be for a heat pump?
The first thing to remember is that if your home is old and not very air tight, your existing energy bills and levels of comfort will already reflect this.
Improving the insulation of your home is always a good idea to make your heating more energy efficient and your home warmer, but of course it is not always practical, desirable or legal (in the case of listed buildings) to change the historic fabric of a house.
As long as you have a powerful enough electricity supply to power a heat pump large enough to meet the heat loss demands of your home, it will work perfectly well to keep your home comfortable.
Whether your heating will be cheaper to run using electrical energy to power a heat pump or not will depend on the comparative price of electricity versus the fuel you were using previously at the time that you install the new heating system and how efficient you can make your system during the install - including any insulation measures you undertake. A good estimate of comparative running costs should be part of the system design you are provided with during the decision making process.
As heat pumps work by moving heat from the surrounding environment into your home they are always more efficient than direct electrical heating and are low carbon heating systems compared to those that rely on burning fuel, which is a much less efficient way to generate heat.
It is worth remembering that investment in solar panels and electric battery technology to power your heat pump can further reduce running costs and increase cost benefit and speed return on investment of a heat pump vs a gas boiler.
STIEBEL ELTRON partners are equipped with quotation tools that provide clear guidance on how much electricity a system will use and what effect this will have on your heating bills compared to an oil boiler or gas boiler.
A bivalent or hybrid heating system for retrofit situations
Do you need a another heat source with a heat pump? Usually no. But it is entirely possible to install an air or ground source heat pump without removing an existing legacy system running on fossil fuel.
A hybrid heat pump system like this can help reduce reliance on fossil fuels and allow a more gradual transition to a fully renewable system by just burning fossil fuels in the very worst cold weather. Heat pumps for this kind of system can be air or ground source and will provide heating and hot water.
Typically the renewable system will cope for 80% of the heating season until the emitters need to run really hot (when the outside air is at very low temperatures), at which point the heating mode will switch to bivalent and the fossil fuel system will kick in in tandem or take over completely.
Is an older home better with an air source heat pump or a ground source heat pump?
Either type of heat pump is suitable for older homes. Older properties often benefit from larger outdoor space which can make it easier to install a ground loop for a ground source heat pump or find a place for the an air source outdoor unit.
Whichever you choose the principle is the same - your heat pump will take heat from the outside, asborbing heat from either air or ground and use it to heat your home.
Single phase heat pumps for retrofit situations
Many heat pumps are designed for three phase electrical supplies. But in the UK most homes have single phase supplies - and older rural properties in particular may have a weak supply that can rule out the installation of some heat pumps because they place too much demand on the supply when starting.
Stiebel Eltron UK supplies a range of single phase heat pumps for just this eventuality. Our inverter-driven air source heat pumps are an ideal choice in these circumstances. And we even have ground source heat pumps 15+ kW from a single phase supply.
Do I need to change to underfloor heating?
Heat pumps are more efficient and have a longer lifespan if used to produce hot water at lower temperatures than typically produced by boilers. This means that in order to have fast response times you need heat emitters with a larger surface areas.
Obviously this makes underfloor heating ideal but it is not essential. Often a good result can be achieved by swapping a few radiators on an existing wet central heating system for larger models. Alternatively, you can simply adjust your expectations of how quickly the house will be brought up to temperature when the heating has been turned off or keep the house at a lower standby temperature rather than completely turning the heating off altogether.
Easy to install heat pumps and hot water cylinders
When you aren't building from scratch with the ability to make allowances for the addition of plant rooms, you need products that are designed to fit into whatever space is available.
We have products that have an outdoor or indoor unit, and have special design modifications to allow them to be fitted into small or narrow spaces we can help with almost any design requirement.
For example some of our integral hot water cylinder and buffer tank units can be split in two for easy installation!
Heat pumps for new build
New build homes are well insulated with low heat loss and require minimal energy use for heating. Most heat pumps will work at high efficiency in such situations and the main consideration may be to make sure that it is actually small enough to ensure the very highest heating efficiency whilst still being able to produce enough hot water for a modern home potentially with multiple bathrooms and ensuites.
Ground and air source heat pumps for cooling a new home
In modern homes the cooling capability of heat pumps can also be a real bonus, so consider whether you need this functionality. Different types of heat pumps provide different types of cooling - some air source heat pumps can provides active cooling whilst ground source heat pumps can be used for active or passive cooling.
The cooling achieved with a heat pump is not generally as dramatic as using air conditioning units as obviously this is not their primary function, but can be sufficient for the mild UK climate and means that you do not need to pay for a separate air conditioner unit.
Building ground or air source heat pumps into your architectural plans
If you are able to influence design choices during the build then an underfloor heating system can be incorporated from the beginning to provide the best match for your heat pump. Space for the heat pump itself, a ground loop or borehole if choosing a ground source heat pump and a hot water cylinder and any other associated system components can also be planned in advance.
The cost of heat pump in a new build home
There is no special funding for installing a heat pump in a new build home because the cost differential between installing a fossil fuel boiler such as a gas combi boiler and a heat pump from scratch is not as great as that between replacing an existing system with a heat pump compared to simply plugging in a new boiler. For this reason heat pumps are becoming the defacto choice of most self-builders who can calculate the short payback period to cover any additional costs and consider their carbon emissions.
Conclusion: heat pumps for all kinds of homes
Heat pumps are a viable and eco-friendly heating and cooling solution for all kinds of homes when correctly designed for the size and age of building.
With different types of heat pumps to choose from there is a suitable option for almost every home and heating system.
Heat pumps can provide home owners with reliable, natural heat and hot water year round by absorbing heat from the outside air or ground and transferring that heat energy to your home.