Frequently Asked Questions
Will my home still be warm enough?
Yes, you just need to ensure that the air source heat pump is sized to meet the maximum heat load conditions for the property. You will experience a gentler more consistent heat within the room. Not like the pulses of high temperature we currently experience with oversized convntional boilers. The thermostat and radiator controls work in exactly the same way.
Will my water still be hot enough?
Most people feel comfortable bathing in water at circa 42c. Conventional boilers produce intense bursts of hot water at circa 70c, which then require lots of dilution with cold water to produce the right temperature to bath in. At 60c+, hot water from a Green Air system is more than warm enough for a bath…you just need to dilute it with less cold water.
How noisy?
The largest green air unit has a decibel level of 53 db, which is similar to the noise level produced by a large fridge. As a comparison noise level normal conversation is 60 -70 db and the telephone dialing tone is 80 db. The smallest 5kw Ecodan unit is the quietest in its class at between 40 - 45db, which means it is almost silent from 1metre away.
Just how efficient are air source heat pumps?
Compared to coal, oil, lpg and gas boilers a well installed air source heatpump can be anywhere from 250% to 500% more efficient
Do I need a new tank?
Yes you will need to change your tank to a higher efficiency cylinder with a separate coil to accept the air source heatpump
Is the tank the same size as my existing tank?
Twin coil tanks are generally larger than conventional tanks as they are designed to accommodate the steady flow rates of 60c water produced by the air source heat pump, rather than the short pulses of 70c+ water produced by a conventional boiler. in general terms a twin coil tank is approximately 10cms deeper and 10cms wider than a conventional tank although this may vary depending on the specific requirements of your system.
Can it work with my existing radiators?
It should work with your existing radiators on most occasions, however due to some of the low flow rate temperatures created by the green air system, it may be necessary to increase some of the radiator sizes. Historically, some heating engineers have sold oversized gas or oil boilers coupled with undersized radiators that then need to get super hot to deliver the required temperature. Heating water to temperatures far higher than is required is obvioulsy hugely inefficient. A Green Air system delivers hot water at the most efficient temperature required to deliver a 21c internal room temperature, and needs radiators that can deliver that heat load effectively.
How efficient is my existing boiler?
A modern condensing gasboiler operates at circa 90-95% efficiency, which is significant improvement on older gas or oil boilers which operate at efficiency levels as low as 55%. The performance of a modern boiler sounds efficient, until you compare it to the 300%+ that the Mitsubishi Ecodan unit produces. To find out exactly how efficient your boiler is, email us at info@greenairheating.co.uk and we will get back to you with the official statistics for it.
Can I take advantage of off-peak electricity tariffs?
A Green Air central heating system will start work earlier than a conventional boiler, so you will get maximum benefit by taking advantage of an economy 7 tariff - which in most areas means cheaper rate between 1.30am and 8am. If you are not on a tariff like this we recommend you switch.
How long will it take to pay for itself?
We estimate that a Green Air Central Heating system will cut your home heating bill by up to 40%. The Government is launching the Renewable Heat Incentive (RHI) scheme in April 2011 which is designed to generate a 12% a year return on investment (ROI) with annual payments of upto £1000 a year. Any system fitted before then will still be eligible to recieve RHI payments. If we assume an average energy bill saving of £500 a year, plus a 12% ROI, customers should expect payback within 4 - 6 years depending on the size ofthe system. Bear in mind that you should also include the likely cost of replacing your existing oil, gas, or LPG boiler, plus a significant increase in gas and oil prices over the next 10 years, so payback in individual cases could be even quicker. If oil and gas prices continue to rsie at the same rate as the last 5 years, by 2020 the average fossil fuel heating bill will be over £4000/year.
I have an old house. Can I install a Green Air system?
A green air system is compatible with most types of housing. Most properties that can achieve a reasonable level of thermal insulation are suitable for an air source heat pump. In order to achieve the highest levels of efficiencies, all properties should have been updated with the basic thermal improvements i.e. cavity wall installation, loft insulation and double glazing. The air source heat pump then needs to be able to meet the maximum heat demand of the property under its maximum (coldest) conditions.
Do they work at night or on cold days?
The green air system will work at ambient temp as low as -20C.
Does the system need any special maintenance in winter?
During the cold spell please ensure the correct amount of inhibitor is put in the system to prevent it from freezing. Recommended inhibitors are Fernox ALPH11 or Sentinel X500
How can I make my Green Air Central Heating system 100% green?
The efficiency of an air source heat pump means that switching from a fossil fuel based heating systems to a Green Air one will dramatically reduce your homes CO2 emissions, even if your electricity supplier only generates power from fossil fuel power stations. However, if you switch your electricity supplier to a “renewable only” company, then you could argue that your CO2 emissions from domestic heating fall to zero, making your home heating 100% green!
How much space do the air source heat pump units need?
To allow for safe operation and safe servicing of the unit, a unit would be placed outside on a purpose built platform measuring 1200mm x 1200mm and the unit would have to have a clearance height of 1600mm. Please note that this applies to the largest unit only.
How close does the air source heat pump need to be to my hot water tank?
Your hot water cylinder could comfortably be 50m from the unit, however, the closer the unit, the better the efficiency.
Can I use my existing central heating system pumps?
Yes, but in most cases we would receommedn that they be changed.
Are there government grants available?
The Government offers grants of up to £900 through the Micro-Generation Scheme. The grant are offered retrospectively and can only be applied for after installation. From April 2011 the Renewable Heat Incentive scheme will pay homeowners upto £1000 a year for generating heat sing an air source heating system. The scheme is designed to deliver a 12% return on investment and is signifiant evidence of how keen Government is to reward those switching to sustaiable heating systems. Green Air will be happy to guide you through the process.
How long do air source heat pump’s last?
The Mitsubishi Ecodan unit is designed to last for 20 years, provided it is properly installed, serviced and maintained.
How much servicing do they need?
The Mitsubishi Ecodan comes as a factory sealed unit (similar to the domestic fridge) and hence requires very little long term attention. We suggest that there is a yearly clean up of any build up of leaves or debris from behind the unit and that the coil is washed annually.
Can I run hot water heating and central heating at the same time?
Yes, you just need to ensure that the air source heat pump is sized to meet the maximum heat load conditions for the property.
Do I need planning permission?
At the moment, yes. You will need to contact your local Planning Department via www.planningportal.gov.uk . We expect air source heating to be granted "permitted development" status soon, but until then this formal process hasto be undertaken. You will also need to notify your Building Control department. Both departments will only be concerned with noise and vibration and proximity to neighbours. As the Mitsubishi Ecodan is the quietest air source heat pump on the market, you should not experience any obstacle to installing your system.
If I recommend a Green Air system to a friend, will you pay me an introduction fee?
We want to make sure that you benefit from recommending Green Air by offering you a financial ”thank-you” for every installed Green Air system generated from your referrals with a cash benefit. Contact us or ask your Green Engineer about how we can reward you for recommending Green Air Central Heating.