01/02/2026
We always recommend that our clients specify separate systems to do DHW and space heating. ✅
Experience has shown us that having one system to do both, results in neither being done very well
Heat pumps serving heating systems should always be looking to reduce flow temperature based on the internal and external temperature to maximise efficiency
Stored hot water should be maintained at 60degrees and so requires a flow temperature of around 65degrees ♨️
Using one system to do both will mean that the system has to ramp up from the weather compensated temperature to 65degrees every time water is drawn off making the systems inefficient
If it doesn't ramp up when water is drawn off the DHW temperature drops below 60 and you risk low DHW temperatures ❌
Because we have always run boilers at high temp, we have always used the same boiler to do both and have carried this mentality forward
Do this with a heat pump and the result
is high running costs 💷💷💷
Yes, you have to buy 2 heat pumps, but you probably have to buy a bigger one and also have to spend money on extra hydraulics , 3 port valve and BMS controls
In many applications the DHW load is very small
On this project, we supplied a
midea MARS heat pump
This model gives 35KW with 65/55 flow and return temperatures (-5 ambient)
It cost about the same as the extra cost of making the heat pump bigger and the required components and controls
This will be cheaper to run than standalone system
The unit also uses propane refrigerant making it future proof
If you would like to discuss what is the most efficient and cost effective solution for your next project, please get in contact ☎️
