Is in-slab heating right for me?
It really is very simple and cost effective. However, there are a few things to consider and it is best to talk to ecoMaster to find out more. Anyone building a new house will get a benefit from in slab heating compared to just installing wall mounted heat pumps. How to get maximum benefit requires consideration of insulation, house orientation to north etc. On this basis, some houses will be much more efficient to run due to thermal gain and design factors. There may be differences in foundation structure for TC1, TC2 and TC3 land.
How does it work?
Hydronic heating has been used for centuries. The Romans used it for home heating about 2000 years ago. Only recently has it become an affordable option for anyone building a new dwelling.
The heat pump heats water and circulates it through a network of pipes laid in the floor. The house is divided into a series of zones or regions and controlled by a manifold placed inside the house. By circulating the water on a frequent basis the slab is evenly heated. Overall control is set by a thermostat placed in a neutral heat zone in the house. This means it will not shut down due to high heat from the sunny side of the house and keep on running due to being on the cold side of the house. Generally the temperature can be programmed to go down to a pre-determined temperature before the heat pump starts heating the slab up again.
What else should I do to make my home more energy efficient?
Talk to someone who has recently built a new home and installed in-slab heating. Contact us for someone to talk to. PVC window joinery has superior heat transfer properties compared to aluminium joinery.
How do I get the best results?
This varies from house to house and personal comfort levels. We can advise on who to talk to regarding insulation, building materials, thermal gain and losses. We can also provide information on the best size of heat pump for in-slab heating and hot water heating.
Is it expensive to run?
It is no more expensive than air to air heat pumps and quite often less expensive compared with or where under tile electric heating is used in bathrooms and kitchens. The system can be set up to use night rates for the heat pumps and energy is stored for when it is most needed. The use of solar PV can significantly reduce the operating costs by accumulating energy during sunny periods and storing energy for when it is required.
Am I better to have a slightly over rated heat pump compared to an optimally sized unit for my new build?
A bigger heat pump will cost more to purchase and heat water quicker than a smaller heat pump. However, a heat pump rated to the house size in most cases will be perfectly adequate. When there is an exceptionally cold or prolonged cold period a small heat pump may not meet the total heating needs of the house.
Will it affect my (wooden) floor as the concrete slab changes temperature?
No. If the slab has been properly prepared and the wood stuck down correctly the heat in the slab will not affect any flooring. Some carpet underlays may act as a thermal barrier and you should check this with your carpet supplier. In some situations, the in-slab heating may be used to help dry out the framing prior to gib being applied.
Does it work on really cold days?
Yes; but not quite as efficiently as on warmer days. However, it is superior to air to air heat pumps as the heat is evenly distributed throughout the house and gently released over time.
Can I and should I alter the temperature room by room?
You can turn rooms off but generally leaving them on means the house is evenly heated with minimal losses. You can only alter the overall temperature throughout the house.
What happens to the system in summer or when I am not using it?
Nothing. If you have solar PV this energy can be exported back to the grid or used to heat hot water.
If I have a dual heat system is it easy to change my preferences to ensure adequate hot water when I need it?
Can I use it for cooling like air to air heat pumps?
No. However, a well-designed house with adequate eves will be cool during summer times. Ventilation should be considered as a means of keeping air fresh in the house.
How much more than air to air heating does this cost?
Don’t look at the upfront cost. You should look at the operating cost for whole of house heating and the savings that can be made.
What sort of return can I expect from in-slab heating compared with air to air heat pumps?
Heat pumps generate 4 times the energy compared to normal convection heaters. Air to air heat pumps distribute heat through air movement. Some people find this uncomfortable and often feel the cold coming up through the floor even though the air is at the required temperature. For the same operating costs as an air to air heat pump an air to water heat pump will evenly distribute energy throughout the slab and release heat gradually over time.
Should I have dual heat HW and in-slab heating or run two separate heat pumps?
In some cases, dual heat will work perfectly well. This is where a heat pump is used to heat both the hot water for showers etc and the slab. However, in some cases where there is irregular requirement for hot water having two heat pumps can be beneficial. The cost of two heat pumps is only marginally more expensive than having one large heat pump.