Waste water heat recovery is a relatively new way to reduce your domestic hot water load, cut CO2 emissions and save you money. Until recently most CO2 savings in a home are focused on reducing space-heating loads. This was done with low or zero carbon technologies.
However, these have been tested to their limits, especially on builds/ sites with small spaces. But there is another way to reduce CO2 emissions from your home. By reducing your domestic hot water loads.
Did you know that your domestic hot water use could amount to 49% of your total heat load (large detached house)? This figure rises to 77% for a small mid floor flat. Waster water heat recovery technologies have the potential to save you money.
What is waste water heat recovery?
A waste water system will recover the heat from your shower or bath by running your waste water through a heat exchanger. This waste heat is then transferred to the cold feed to your combi-boiler (or cylinder), and then through the cold feed to your shower. This pre-warms the water.
10 benefits of waste water heat recovery
Here they are. The 10 benefits to installing a water heat recovery system.
1 They reclaim up to 60% of the heat you normally lose down the drain
2 They save you money on your heating bills
3 They work year round
4 They are very easy and quick to install
5 They are undetectable once installed
6 No maintenance is needed
7 They have no moving parts
8 High SAP points that can improve a new build by 5-8% (in line with revisions to part L of building regulations for 2014)
9 Will help a new build achieve CFSH code 3
10 Green deal approved
Although there are great benefits to installing a waste water heat recovery system, to really get the best you need to follow some general rules.
- To maximise your benefits heat should be removed from all showers in your home
- The most effective systems feed pre-warmed water to both the shower and your boiler
- You should choose a system with a high heat exchange
- Most systems need a cold water pressure of at least 1.5bar
- Make sure you look for the WRAS logo (so that the system complies with water regulations authority scheme)
The average price for a single unit is around £400. Installing a waste water system should be a last resort to reducing your domestic hot water load. You will be better off by using less in the first place than by re-using what you do.
Image: Steven Depolotagsheat recoverywaste waterwaste water heat recoverywwhr