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The Renewable Heat Experts Design | Supply | Installation | Maintenance.
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Biomass Heating Solar Heat Pumps

Frequently Asked Questions

Here are answers to the questions we get asked most often. If you have a question about biomass heating, solar, air source heat pumps or anything else related to renewable heating then please do get in touch.

Do you do wood burner installations?

Yes we do install wood burning stoves in domestic properties, the question that is important to raise is the flue considerations as this is the bulk of the installation cost. We can do flexible flues for wood burners into existing fireplaces (subject to a site visit to survey conditions) or with a hard flue that in most cases would be external. We typically do not source wood burning stoves ourselves but our cost to install wood burners to industry standards is competitive.

What is the most efficient way to heat and supply hot water to a domestic dwelling?

This is a very difficult question to answer as there is no one right answer. It is purely down to the characteristics of the dwelling. If for example the dwelling was a new build and had a heat loss of around 8-9kW then the most practical and efficient way would be a heat pump with in screed under floor heating. We could specify that the installation has a Season Performance Factor (SPF) of 3.5 meaning that over the course of the year the heat pump would be 350% efficient. For every kW of electricity put into the heat pump you would get 3.5kW back in heat. A gas boiler, oil boiler or biomass boiler has a typical efficiency of 90% as some the heat generated by them is lost to the boilers surrounding (which is greater if installed in an external boiler room) and heat is lost in the flue when emitting gases. Condensing boilers are more efficient as the flue temperatures are lower so less heat is lost. All boilers are very efficient, as the market improves so will the means to heat buildings. For dwellings with small heat losses or new builds air source heating is the best method. For larger properties then any biomass technology is perfectly suitable depending on clients' demands and requests.

Which are better, in screed or overlay underfloor heating systems?

That is a technology specific question, as the properties of both heating systems have their merits. An in screed under floor heating system is the laying down of pipe work into insulation boards and pouring a wet or dry screed over the pipes sealing them in the floor. As heat is delivered to the pipes in the floor they will emit heat into the screed which will act as a giant thermal mass and then radiate this heat into the dwelling. In the case of a new build it is always better to go with an in screed installation as it tends to be cheaper than overlay. Screed installations work best for heat pumps as heat pumps operate at lower temperatures (35-50°C) than conventional boilers, so having a giant thermal mass suits the characteristics of a heat pump better. It also gives better scope for the heating. If a room has a large heat loss then the pipe work in the floor can be installed closer together, increasing the amount of heat being supplied to the floor. For a biomass, oil or gas system supplying under floor heating the typical standard is between 200-300mm pipe centres, with air source heat pumps pipe centres are closer together 100-200mm.

Overlay under floor systems are mainly used in retro-fits or for doing under floor heating on a first floor. These come as pre-packaged systems and are installed on top of an existing floor or on insulation in between joists, with a floor covering over the top. They do tend to have pipe centres preset to 200mm so they are perfectly adequate for conventional systems and biomass, they are also more suited to operating temperatures of 60-70°C. They are not the best solution for air source heat pumps unless the manufacturer can guarantee that the under floor will provide sufficient heating to the floor area. They might work well on first floors as they have a heated thermal bridge from the ground floor, but for ground floors if you get an in screed floor it is recommended, the cost to take up the floor might be costly but installation of the under floor will be relatively cheap compared to overlay.

Is my home suitable for a biomass boiler?

Most properties can accommodate a biomass boiler, although there are certain exceptions such as a flat in a block of flats - this would benefit from a district heating installation. Provided that a house, bungalow etc. has the space to accommodate a boiler then in most circumstances it is feasible. A small dwelling could benefit from either a hydro pellet stove or a small pellet boiler. These typically need an area of 1.4m x 2m so that there is suitable clearance for servicing, the boiler's flue can be connected to the boiler and the boiler can be accessed for cleaning. Small hydro pellet boilers are installed in fireplaces or within the building as they are more aesthetically pleasing, whereas boilers tend to be installed in utility rooms, garages or out buildings such as sheds.

Are there any constraints to installing a biomass boiler in a dwelling?

If the building is in a permitted develop rights area usually there is no problem, it is however advisable to get permission from your local council before installing a boiler. If the building is listed or in a conservation area such as an Area of Outstanding Natural Beauty (AONB), Site of Specific Scientific Interest (SSSI) or in a National Park then planning permission must be filled out and permission granted before any work goes ahead.

What are the main constraints to consider for air source heat pumps?

The real constraint with heat pumps is the rating of the electrical supply to a building or dwelling. A 12kW heat pump has the potential to use 30amps in the power supply. Considering that all electrical appliances need an amp supply, this means that by installing an air source heat pump there is the potential to trip the electrical supply. This was more a concern when air source heat pumps first came out on the market. The Panasonic air source heat pumps we install are inverter driven heat pumps. This means that they are soft starting so there is not an instant drain on the amp supply to the dwelling. We do recommend that for a domestic dwelling that they have an amp supply of 100amps for the installation of an air source heat pump. It is always worth investigating the electrical supply to your dwelling with your energy provider or the network provider.

The other constraint with heat pumps that will be addressed at a site visit is the location of the heat pump and the noise pollution that could potentially affect surrounding inhabitants. A heat pump when running at maximum power can reach up to 50dB (decibels) and if this is near to a habitable room such as a neighbour's bedroom then there is the potential for the heat pump to not be deemed appropriate for installation. We carry out noise pollution calculations to see whether installing a heat pump is a reasonable solution. Typically a heat pump that is installed against a flat wall will be permitted if the heat pump is >4m away from a neighbours habitable room. In most circumstances an air source heat pump is sited as close its intended amenities (hot water cylinder, heating system) as possible which usually is away from habitable rooms.

Are there problems with air source heat pumps and electric showers?

This might seem like a peculiar question but there is potentially a problem installing an air source heat pump to a dwelling or building that has an electric power shower. The reason for this is the amps that the components use. Typically a dwelling has an 80-100amp circuit breaker meaning that if the amps being used by the anything plugged into the mains exceed the circuit breaker then the circuit will blow and knock out the power supply to the house. An electric shower typically requires a constant demand of 30amps whilst it is in use as can potentially a heat pump. This means that if both are used at the same time then 60amps from a maximum of 100amps are being used, then if you add in the other day-to-day electrical components that are used such as televisions, cookers, microwaves, fridge freezers, laptops, computers etc that are in use then the circuit breaker in the building will trip and the power supply be shut off to the building. In most cases if a dwelling is installing a heat pump then the electric shower is removed as the hot water for the dwelling will be provided by the heat pump, but it is an aspect that will be looked into and asked about at a site visit.

Are special hot water cylinders made to accommodate solar thermal and heat pumps?

The answer is yes. As the renewable sector grows so too does the demand for more efficient hot water cylinders. In the case of thermal it is simply the addition of a further hot water coil in the cylinder. This is usually in the upper part of the cylinder, but this coil can also be in the bottom of the cylinder. As a solar thermal panel requires a gycol mixture for heating fluid transfer with the cylinder (as this has a greater thermal conductivity than water) a solar thermal panel can still provide or top up a hot water cylinder in the winter. In the case of air source heat pumps, they have made specialised cylinders for these renewable technologies. The coil within the cylinder has a greater area than a conventional hot water cylinder so that the maximum amount of heat is extracted from the heat pump.


We supply and install a wide range of biomass boilers, biomass stoves, air source heat pumps and solar systems from manufacturers including:
ETAFrolingMCZ HeatingEco AngusGrantNordica Extra FlameVaillantPanasonic
Microgeneration Certification Scheme Approved Installer and NAPIT Approved Electrical InstallerGreen Deal Approved InstallerRenewable Energy Consumer CodeRenewable Energy Hub Approved Installer
We serve a wide area including Somerset and Devon, Exeter, Wellington, Taunton, Shepton Mallet, Street, Glastonbury, Wells, Frome, Minehead, Bridgwater, Weston-Super-Mare, Bristol, Dorset, Wiltshire and Cornwall.
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