Air Source Heat Pumps for your home (ASHP) A very environmentally friendly option for your heating and hot water
These devices typically sit outside next to your home. Essentially ASHP uses the same technology as a fridge, only in reverse. Air Source Heat Pumps take the heat from the surrounding air via a fan, which gently heats a conducting liquid. This liquid is then compressed to raise the temperature to a useful level. This heat is then transferred to either a cylinder for storage or house heating and being deemed “low grade” heat is ideal for underfloor heating.
Another positive is installation is normally straight forward, the units themselves are often affordable (when compared to other renewable technologies), and uses technology which is tried and tested and very reliable.
The effectiveness of an Air Source Heat Pump is measured by its Coefficient of Performance (CoP) which provides the amount of Kw of electricity it takes to run the unit compared to the Kw of heat produced.
What are down sides to Air Source Heat Pumps?
Air temperature varies and the lower the ambient air temperature the less energy is available and typically, the lower the CoP, so whilst many ASHP’s can produce heat down to -15C, the efficiency drops off at low temperatures which is when you have the greatest need for heat. Also, the units themselves are not silent with different manufacturers ASHP’s producing varying noise output, and so it is worth checking the noise levels before deciding which ASHP. Finally ASHP’s are best suited to under floor heating as this enables the unit to run at lower output temperatures (making them more effective in colder weather).

So when would an Air Source Heat Pump work for my home?
ASHP can deliver savings, especially when they are used in conjunction with underfloor heating ( wet systems ) and used in well insulated homes. In these circumstances an ASHP could provide heating all year round with significant savings during the spring, summer and autumn.
We recognise a key consideration for many is the initial cost, however, with the governments Renewable Heat Incentive (RHI) program house holders can receive 4 payments each year (quarterly) for 7 years which should offset the majority and potentially all of the initial outlay. There are conditions attached to receiving the RHI payments, many of which are explained in the attached FAQ’s document from Ofgem (2017) ;
https://www.ofgem.gov.uk/ofgem-publications/121709
If you would like to discuss ASHP and whether it could be right for you, please email (enquiries@ahs-heating.vps16.digitoolbox.com ) or call AHS who will be delighted to help.
How does a heat pump work?
High Efficiency Viessmann Boilers Viessmann Gas Boilers
Viessmann’s domestic product range has been built around a long established reputation for high quality commercial heating systems. Viessmann manufactures all of its own products and controls to ensure that the drive for quality remains throughout the entire range and that there are additional benefits from combining its heating technologies.

Vitodens 100-W
Wall Hung High Efficiency Gas Boiler
Suitable for both new build and replacement applications on sealed systems, the Vitodens 100-W Combination, Compact and System boilers combine great performance with easy installation and maintenance.
Features:
- Rated outputs: 26 kW, 30 kW and 35 kW
- 10 year warranty on the Inox-Radial stainless steel heat exchanger
- SEDBUK rated
- Modulating MatriX pre-mix cylinder burner
- Integral AquaBloc hydraulic unit for easy service & maintenance
- Pre-heat function on Combination models
- Extremely quiet operation
Dimensions: Depth – 350mm  Width – 400mm  Height – 700mm

Vitodens 200-W
Wall Hung High Efficiency Gas Boiler
A feature of this model is the specifically developed automatic combustion controller Lambda Pro Control, it ensures a standard efficiency of up to 98% (Hs) / 109% (Hi) and consistent high energy efficiency.
Features:
- Modulation range of 1:6
- Exceeds SEDBUK minimum efficiency requirements
- Self-cleaning smooth stainless steel Inox-Radial heat exchanger with 10 year warranty
- High corrosion resistance through high grade stainless steel 1.4571
- Unique MatriX cylinder burner with long service life through stainless steel MatriX mesh
- Optimum matching of heat exchanger and burner
- Lambda Pro combustion controller automatically adjusts combustion for fluctuations in gas quality, which extends the life of the boiler and service intervals
- No nozzle change required when changing for LPG
- Consistently high efficiency even with fluctuating gas compositions
- Constantly clean combustion
- Low combustion noise through low fan speed
Dimensions: Depth – 360mm  Width – 450mm  Height – 850mm
High Efficiency Viessmann Boilers Viessmann Oil Boilers
Viessmann’s domestic product range has been built around a long established reputation for high quality commercial heating systems. Viessmann manufactures all of its own products and controls to ensure that the drive for quality remains throughout the entire range and that there are additional benefits from combining its heating technologies.

Vitorondens 200T
Floor Standing High Efficiency Oil Boiler
The Vitorondens are floorstanding oil condensing boilers with an attractive price to performance ratio. Â Also with compact dimensions. Â It is based on the Vitorond 100 cast iron boiler, proven over many years. The Vitoflame 300 Unit blue burner is designed for use with all commercially available low sulphur fuel oil.
Features:
- Vitotronic control unit
- Wide water galleries and large water capacity
- Biferral cast iron and steel composite heating surface
- Vitoflame 300 Unit blue flame oil burner
- Highly effective thermal insulation
- Inox-Radial heat exchanger
- Integral silencer
Dimensions:
(20.2 to 24.6kW) Depth – 940mm  Width – 500mm  Height – 1226mm
(28.9 to 35.4kW) Depth – 940mm  Width – 500mm  Height – 1362mm
(202 to 24.6kW) Depth – 940mm  Width – 500mm  Height – 1662mm
Vitovalor – Hydrogen Fuel Cell heating solution A exciting green energy solution combining heat & power for your home
The Vitovalor is an incredibly efficient, environmentally friendly, home heating solution – the latest in heating technology. It provides simultaneous heating and hot water using advanced fuel cell technology to convert hydrogen into energy.
The Vitovalor can produce a thermal output of over 30KW, enough for an average 4 person family of an averagely insulated house, and has a maximum electrical output of 18Kwh over the course of the day, sufficient to cover the basic requirement of a household (when paired with a power storage solution, all the energy produced could by the home owner). This leads to lower energy costs, less Co2 and greater independence from external power suppliers.
Key Features
- Up to 30% lower energy bills compared with gas condensing technology
- Protect the environment through lower CO2 emissions
- Compact design with a small footprint
- Energy efficiency class: A++

Combined Heat & Power and Hydrogen Fuel Cells Explained
Combined Heat and Power, also referred to as CHP, is where a device creates both heat and electricity from the same unit. Typically a CHP unit is actually designed to produce electricity and the byproduct of this process is heat, which is used for the central heating and hot water. CHP units have been available since the 1970’s but typically for industrial or commercial applications until relatively recently.
About the Viessmann Vitovalor
The hydrogen fuel cell used within the Viessmann Vitovalor uses an electrochemical reaction, referred to as cold combustion.
The principle is basically quite simple: Hydrogen contains positive ions and negative electrons. These are separated and the negative electrons then migrate from the anode to the cathode to create electricity. The byproduct of this chemical reaction is heat which is used for central heating and domestic hot water.
Solar Systems

Solar Photovotiac Systems (PV)
Solar PV remains as viable as ever, in fact with a massive fall globally in panel prices.  It offsets the fall in the FIT tariffs to provide an ROI of 8 – 12%, pay back in as little as 7 years and an income for 20 years. Commercial properties with arrays greater than 10kW can generate an even higher ROI.
Home owners and business may perceive that solar has had its day, but more panels were installed last year than ever before in the UK. Â Most of these went on large solar farms where investors still appreciate the value of the return generated.
The feed in tariffs or FITs have dropped dramatically since introduced in 2010. Â As of July 1st 2013 they will stand at 14.9p for a domestic array under 4kWp.
The rate now has a control mechanism to introduce cuts at a steady rate of 3.5% every quarter, however, this is subject to the number of installations carried out and can be held off for up to 3 periods before a drop is automatic. Â Export rate is currently 4.64p (July 2013). Â Once signed up your rate is fixed for 20 years with increases in line with the Retail Price Index (RPI).

Solar Thermal
Solar water heating (known as solar thermal) systems capture the free heat from the sun and use it to heat up water for use in the home. It’s a simple process. The panels on your roof absorb heat from the sun – they are known as the collector, then the water in the panels heats up, this hot water is pumped through a coil in your cylinder, which transfers the heat to the water in the cylinder.
AHS Ltd can design, supply and fit a solar thermal system to suit your needs, whether for your household needs or something larger for industrial requirements, we can help.
The Viessmann range includes:
- Solar PV Systems
- Solar Thermal
- Heat Pumps
- Biomass Boilers
- Combined heating and power stations
- Bio-Gas
- Waste Heat Boilers
All products are part of a coordinated and complete system, where all components fit precisely together. Only the perfect interaction of integrated system components draws out the maximum potential of innovative, leading edge technology.
What are the alternatives to gas/oil boilers? If you are considering a more eco-friendly option for your gas heating we can help you make the decision.
At AHS, we believe Renewable Energy is the future, with rising energy costs and rising Co2 levels it has never made more sense, to see if renewable energy works for your home and your pocket. With technology constantly improving and changing, it’s a challenge to make an informed decision. In order to help make sense of the renewable energy marketplace we have explained the main choices available to the consumer:
Â
- Electricity only
- Heat only
- Heat and Electricity ( known as CHP, Combined Heat and Power )

Heat only
Air Source Heat Pump (ASHP)
These devices typically sit outside next to your home. Essentially ASHP uses the same technology as a fridge, only in reverse. Air Source Heat Pumps take the heat from the surrounding air via a fan, which gently heats a conducting liquid. This liquid is then compressed to raise the temperature to a useful level. This heat is then transferred to either a cylinder for storage or house heating and being deemed “low grade” heat is ideal for underfloor heating.
Another positive is installation is normally straight forward, the units themselves are often affordable (when compared to other renewable technologies), and uses technology which is tried and tested and very reliable.
The effectiveness of an Air Source Heat Pump is measured by its Coefficient of Performance (CoP) which provides the amount of Kw of electricity it takes to run the unit compared to the Kw of heat produced.
What are down sides to Air Source Heat Pumps?
Air temperature varies and the lower the ambient air temperature the less energy is available and typically, the lower the CoP, so whilst many ASHP’s can produce heat down to -15C, the efficiency drops off at low temperatures which is when you have the greatest need for heat. Also, the units themselves are not silent with different manufacturers ASHP’s producing varying noise output, and so it is worth checking the noise levels before deciding which ASHP. Finally ASHP’s are best suited to under floor heating as this enables the unit to run at lower output temperatures (making them more effective in colder weather).
So when would an Air Source Heat Pump work for my home?
ASHP can deliver savings, especially when they are used in conjunction with underfloor heating ( wet systems ) and used in well insulated homes. In these circumstances an ASHP could provide heating all year round with significant savings during the spring, summer and autumn.
We recognise a key consideration for many is the initial cost, however, with the governments Renewable Heat Incentive (RHI) program house holders can receive 4 payments each year (quarterly) for 7 years which should offset the majority and potentially all of the initial outlay. There are conditions attached to receiving the RHI payments, many of which are explained in the attached FAQ’s document from Ofgem (2017) ;
https://www.ofgem.gov.uk/ofgem-publications/121709
If you would like to discuss ASHP and whether it could be right for you, please email (enquiries@ahs-heating.vps16.digitoolbox.com ) or call AHS who will be delighted to help.
Ground Source Heat Pump (GSHP)
This technology uses pipes that are buried in the ground to extract heat, and can be used for heating and hot water. A ground source heat pump circulates a mixture of water and anti-freeze around a loop of pipe which is passed through a heat exchanger into the heat pump. Since the ground stays at a fairly constant temperature under the surface the heat pump can be used throughout the year. The pipes used are typically either:
– ground mats which are a series of pipes buried not far below the surface (typically a metre or so). This requires a fairly large area (dependent on the heat requirement) and care when digging the garden! or
– Bore holes. These bore holes remove the ground mat concerns but the depth per bore hole can be between 60 metres to 150 metres and so the ground work costs are the most expensive part of the installation.
Biomass
Currently available are either a biomass-only boiler, fueled by wood pellet, wood chip or logs, or a biomass pellet stove with a back burner (this includes boiler stoves). If you have your own wood supply or for those with good access to replenish the wood fuel this is a viable option but will naturally tend monitoring more than conventional heating and of course, burning wood releases the Co2 within the wood to the atmosphere so whilst renewable is not carbon free.

Electricity only
Solar PhotoVoltaic (PV) panels
The most common form of renewable electricity generation are Solar PhotoVoltaic (PV) panels. Typically installed on the roof these PV panels make electricity using the sun’s UV so work even on cloudy days. PV panels are a truly renewable energy source and usually have a long life span, they can be 25 years or more, so there is a great opportunity to get a good return on your initial installation investment.
They also require minimal maintenance so the overheads are low. All sounds good so far, but of course the downside is they rely on sunlight. This means zero power is produced at night, and very low light levels can drop their efficiency by a large degree. Since many households often require more electricity in the evenings (lights on, watching TV, putting the washing on, etc ) the lack of available electricity means reliance on the national grid.
One way to minimise this is to use battery storage, so that excess power created during the day is stored and used when its dark. We at Alexandra Heating Services believe battery technology will need to be an ever increasing part of a renewable energy solution.
Hydro Power
If you are fortunate enough to have a stream or river in your garden, and you have permission, the power of flowing water can drive a turbine which drives a generator to produce electricity.
This is a true renewable and has the advantage of being constant, so can produce electricity day and night, and depending on the amount of water and its speed, can produce really useful power. Installation costs will vary but Hydro has the potential for a good return.
The key is ensure you have all the permissions (probably planning permission and the environmental agency should be engaged).
Heat only
Solar Power Water Heating
Solar water heating systems contain a solar collector that faces the sun and either heats water directly or heats a “working fluid” that, in turn, is used to heat water. These are sometimes referred to as wet systems (for obvious reasons). This is a well known and well used technology and is a true renewable and efficient, however the same downsides as PV exist (no energy produced when its dark) but also has a higher maintenance cost.
Another form of Solar roof panel uses vacuum tubes instead of silicon based (semi conductor) panels. These are glass tubes with an absorber inside within a vacuum. These tubes achieve a higher energy absorption and therefore offer greater efficiency however they are typically more expensive.

Heat & Electricity
CHP – Combined Heat & Power
CHP is a process in which both space/water heating and electricity are produced at the same time. Traditional CHP units have been operating at an industrial / community scale since the 1970s. Now since 2000, with rising energy prices, micro CHP designed for individual buildings has become economically viable.
Effectively the micro CHP unit replaces the conventional gas central heating boiler providing heat and hot water as usual, but additionally providing some of the building’s electricity needs. The European Cogeneration Directive defines micro-CHP as all units with an electrical capacity of less than 50kW.

Fuel Cell
There are several types of fuel cell ( SOFC, PAFC and PEMFC ) but only one of these is currently available for the domestic market which uses PEMFC ( Proton Exchange Membrane Fuel Cell ) and is made by Viessmann and houses a Panasonic fuel cell.
PEMFC is favoured as it requires much lower temperatures to operate, has a large install base in Japan ( we understand more than 200,000 units ) and provides an excellent ratio between heat and power ( nearly 1 : 1 ).
Currently Fuel Cells need natural gas to provide the Hydrogen so if you do not have a gas supply this solution will not ( currently ) work in your home. For information and installation regarding the Viessmann Vitovalor please call or email Alexandra Heating Services.
ECE
Another form of combustion engine is the Stirling engine. These engines are external combustion engines (ECE), which allow continuous, controlled combustion resulting in very low pollutant emissions and high combustion efficiency. In comparison with ICE engines, Stirling engines have relatively long service intervals as well as lower running costs as well as being quieter – which makes them more suitable for domestic applications.
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