Invisible Heating Systems - Underfloor heating, ground source heat pumps, solar & renewable energy systems
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Retro-fitting Heat Pumps


Air source heat pumps are suitable for retro-fitting into an existing building or where there is insufficient space for laying a trench system for pipe.  Installation inconvenience is considerably reduced.

If you're thinking about installing a micro-renewable heating system in your home to replace or work alongside your existing boiler, please read on.

 

Managing Your Expectations

Installing heat pumps into existing buildings isn't always a "cure all".  In a well-insulated property which already has underfloor heating, it’s well worth considering as a direct replacement for your existing boiler.  In an older, less well-insulated house, a heat pump can help considerably but should be understood in the context of the building's construction type, age, insulation levels, hot water requirements and existing heating system.  Heat loss is always a major factor in older buildings. 

We believe that in buildings of all types and age, a mix of renewables can contribute to optimum year-round performance and result in a reduced reliance on conventional heat sources.  An example of this would be a heat pump plus solar panels plus wood-burning stove to ensure heating and hot water in winter and hot water in summer time.  The thermal store is critical; it has the ability to integrate a range of different heat sources (solar, wood-burner, kitchen range) and your existing heating system.

The following points are all key to ensuring heat pump performance, optimised system efficiency and reduced system costs over the long term:


Insulation

We can't emphasise enough how important it is for you to improve the insulation levels in your home.  Conduct your own energy audit and assess how much heat you're losing.  How recently was your attic insulated - and how well?  What level of glazing have you got?  Is the building cavity-wall insulated?

Improve insulation and U-values in any way you can in your property to ensure air-tightness and avoid draughts and heat loss.  Radiators heat quickly but also cool down quickly so it’s most important to insulate your property to retain the heat produced – this is key to lower running costs.  If you have an open fire, ensure a damper is installed.   


COP

Remember the water temperature from a heat pump is approximately 45°C using a 407 gas.  In IHS heat pumps, this would be expected to deliver a COP of up to 1:4.4.  The use of 134A gas will deliver up to 60ºC, however its use means that COP is reduced to 1:3.  Read more about COP here.


Mix of heat sources delivers maximum results

Integration of a number of micro-renewables ensures that the end user is not over-reliant on any single heat source.  The subsequent addition of renewable power sources such as solar PV, wind turbine or small hydro can help power your heating and hot water system. 


Connecting Heat Pumps to Radiators

Many existing houses have radiators - it is possible to integrate heat pumps with radiators but in most cases, radiators need to be increased in size by either 50% or be exchanged for double radiators with fins.  This is due to the lower output of a heat pump (about 45˚C) in comparison with a conventional boiler (70˚C).  A likely exception is older cast iron radiators - they have excellent heat storage capacity (slow to heat, slow to cool) and in most cases, work well with heat pumps.

A heat pump and radiator system will probably have to run during peak electrical tariffs to provide sufficient heat during colder periods. This is why underfloor heating installed in concrete screed is an ideal heat sink and emitter.

If you need to find out if your existing radiators will deliver reasonable output, turn down your boiler to about 45˚C during the winter months and see how it feels.  

 


Diagram showing integration of solar panels to existing radiator system

 

The above schematic shows the stratified tank integrating solar collectors with underfloor heating or radiators.  Heating is supplied by heat pump, oil, gas or biomass boiler.


Location

Heat pumps and Hygienik Tanks are a substantial size.  You will need a suitable area in which to install them, preferably at ground level in a boiler or plant room.  They are unsuitable for attic installation.


Finally

Installing a micro-renewable system isn’t always the most practical solution; sometimes it’s a genuine option.   If you’d like to enquire about the viability of installing a heat pump, solar panels or a thermal store we’ll be happy to give you our honest opinion on possible choices for your property.