Boilers vs Heat Pumps
Traditional boilers tend to be oversized compared to heat pumps in terms of capacity.
As a general rule a house that requires 5kW of energy would tend to have a 30kW boiler installed.
This is because combi boilers are designed to be reactive, providing heating on demand. In this case, your thermostat will monitor your room temperature and turn the system ON and OFF to meet the desired room temperature. This creates a yo-yo affect between desired temperature and actual, and also between your inflow water temperature and your design flow temperature of your system (~35°C for underfloor heating and 45~80°C for radiators).
This greater temperature rise in this scenario requires more power.
Heat pumps heat your water much more gently, over a longer period of time, and keep a constant flow.
Having heat pumps with a 30kW capacity requires an expensive unit, and usually 3-phase power to achieve. As a result, heat pumps are designed more carefully to facilitate lower capacity.
Heat pumps keep water flowing and by maintaining constant temperature in the system, there is rarely a need for a large surge in power to combat dropping room temperatures. The heat pump works to keep the water inflow temperature within a couple of degrees of your design flow temperature, rather than 5~10 degrees, as can be the case in a boiler system.
Adlår heat pumps are installed with extra capacity built in, and in combination with temperature sensors and pre-programmed environmental heating curves, we can account for the worst case scenarios (when outside temperature drops below -10°C, and the hot water temperature isn’t keeping up with your thermostat demanded temperature).
Our extra capacity includes:
- 3kW Immersion heater, within a 60 or 90 litre buffer tank
- 1.5kW domestic hot water (DHW) cylinder air source heat pump (ASHP)
The buffer tank smooths out demand, having heating hot water available to distribute to your heating system. The 3kW immersion heater can be activated if the heat pump’s capacity is close to maximum and the temperature settings aren’t being met by the heat pump alone.
The 1.5kW DHW ASHP cylinder works independently from the heating, to supply only for your domestic hot water. As DHW takes priority over room heating in most systems, by splitting the system as we do, we avoid the heat pump being in over capacity and prevents heating capacity for hot water from ever being diverted to the DHW.