Condensing Boilers, Combination Boilers & Renewable Energy Sources.
Newcastle, Northumberland, Durham, Tyneside, Sunderland & Wearside.
Q. What is a ‘Combi’ Boiler and which one should I buy?
A. A ‘combi’, or combination, boiler is so called because it is a combination of a central heating boiler and instantaneous water heater in one cabinet (usually it is necessary to do away with separate cold water tanks and hot water cylinders, saving a lot of space).
Combis deliver the hot water at mains pressure, which is excellent for showers, but it is very important to ensure that you choose a boiler which will deliver enough hot water for your normal needs – the more powerful the boiler, the more water it can heat in a given time. Both Gas and Oil fired combination boilers are readily available and offer a range of features to suit many homes.
All combis are NOT the same – we would advise using boilers made by well known British or European manufacturers that have good track record of reliability and spares / service backup in this country. We will be happy to suggest suitable models for your needs.
Q. Can I still have an ordinary boiler?
A. Yes! It is still possible to have a conventional floor-standing or wall-mounted ‘heat-only’ boiler fitted. Some installers may find it easier to fit combis and suggest – incorrectly – that other types of boiler can no longer be fitted. There is still a place for this type of boiler and they will continue to be available from major manufacturers. When fitted with suitable up-to-date controls, a condensing conventional boiler should have a very similar energy efficiency to a condensing combi boiler.
Q. What is a ‘Condensing’ Boiler?
A. A ‘Condensing’ or ‘High Efficiency’ boiler is designed to extract about 15% more heat from the fuel burned that a ‘Standard Efficiency’ boiler – it does this by having a heat exchanger which cools the burned gasses to a much lower temperature, thus extracting more heat from them. A large part of the ‘products of combustion’, produced when fossil fuels such as gas and oil are burned, is made up of water vapour. In a standard boiler this is sent out in vapour form at a temperature well above boiling point, however, a condensing boiler cools the gasses down well below boiling point and most of the water condenses out inside the boiler – hence the name. A special Condensate Drain is needed to remove this liquid from the boiler to a suitable drainage point. Some of the condensed vapour is carried out through the boiler flue and is seen as a ‘plume’ of steam-like appearance, especially noticeable in colder weather.
Building Regulations state that almost all new or replacement gas boilers will need to be ‘condensing’ types in order to satisfy the requirements for minimum boiler efficiency. Oil fired boilers for domestic heating installations are now subject to similar regulations.
Q. Can I still have a New Back Boiler Unit?
A. Possibly! No brand-new back boiler installations are permitted (i.e. where a back boiler is not already fitted), BUT, it is still possible to buy back boiler units with fitted gas fire-fronts. Part L of the Building Regulations requires installers to ensure that it is not realistic to install a condensing boiler without causing major disruption to the house before considering replacing an existing back boiler with a new one. There is a good reason for this, Back Boilers are much less efficient than current condensing boilers – typically being in Efficiency Band D or E as compared to Bands A & B for condensing boilers. Whilst they are convenient and space saving, the low efficiency and the fact that they are large ‘open-flued’ appliances (with the attendant safety concerns) means that back boilers are better avoided if at all possible.
RENEWABLE ENERGY SYSTEMS:
Q. What is the average ‘Payback’ time for Renewable systems?
A. At this moment in time, this can vary from about 8 years to 50 years. This will vary according to the type of renewable system being considered, the heat requirements of your home and the complexity of the installation. All of the currently available options will make worthwhile contributions to reducing greenhouse gas emissions, which should be taken into account, also, as production volumes increase so the unit cost of equipment is likely to reduce and coupling this with an anticipated long-term rise in fossil fuel prices, payback time will almost certainly reduce significantly over the next few years.
Someone recently asked a very pertinent question: ‘Would you be concerned about the ‘payback’ time when you buy a new flat-screen television?’ The answer is obvious: firstly, you couldn’t calculate a payback time and secondly, you would want the best set you could afford. So, considering the importance of a heating and hot water system to your day-to-day comfort and the number of hours that your system is in operation, is cost the only concern?
Q. Can I use Renewables with a Combination Boiler?
A. whilst most systems are currently designed around ‘conventional’ heat-only boilers with hot water storage cylinders, some of the newer models of combi boiler, such as the Worcester ‘Greenstar’ ‘CDi Compact’ models can be combined with a ‘Greenskies’ solar thermal hot water system to further reduce running costs.
Q. What sort of Shower will suit my System?
A. Electric showers will suit most systems where reasonable cold water pressure is available. They are convenient to use and heat up almost instantly, so there is no problem waiting for stored water to heat up. Electric showers of up to 10.8kW rating are quite common and when fitted with a good quality shower head give a much better performance than the old standard 7kW showers. Having said that, they do not compare with the powerful sprays available from the best mixer and power showers.
With Combi Boilers, Un-Vented (Mains Pressure) Hot Water Cylinders, or ‘Multi-Point Instantaneous Gas Water Heaters’, choose a good quality mixer shower – this should be either ‘fully thermostatic’ or ‘pressure compensating’ and designed for high pressure systems – regulation do not permit the use a pumped ‘power’ shower with a combi, but a good mixer shower should give you the same level of performance as a power shower without needing a pump. (The same comment applies to ‘un-vented’ cylinders and ‘multipoint’ water heaters.)
With traditional Low Pressure, tank-fed, systems use either a simple gravity-fed mixer shower, or for improved performance, use a pumped ‘power’ shower. It is vital that power showers are piped up exactly as per the manufactures instructions, or operational problems can easily arise. Power showers can be either self-contained (with the pump in the shower casing) or have separate pumps feeding a standard thermostatic or manual shower mixer unit. It may be necessary to notify your water supply company if you install certain types of power shower.