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RADIATORS AND UNDERFLOOR HEATING SYSTEMS Radiators Radiators used to be large iron units (known as 'School Radiators') which took a little time to warm up, but their full bore design, in conjunction with large diameter steel pipework, allowed systems to work by gravity circulation alone. These were replaced by smaller panel radiators in the 1950s/60s, which were usually made from mild steel. Although described as radiators, most of the heat from a radiator is by convection. In the 1970s panel radiators started to be produced with steel convector fins on the rear, which makes a significant improvement to their efficiency by encouraging more convection to take place. |
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Very little innovation has since taken place in the world of radiators; instead of welded top edges we can now have 'roll tops' which are potentially less injurious if you should be unlucky enough to fall on one.
 'Compact' radiators are now the popular choice. These have a panelled in cover where the convector louvres are sited, which looks neater, and prevents items from being lodged inside. Ironically, 'Compacts' are not really any smaller than the normal type.Hot Water & Central Heating recommend and fit the Vogel & Noot 'Vienna Line' range. These Austrian built units have safe, easily cleaned curved edges, and a quality paint finish. Because Vogel & Noot were originally a packaging company, their radiators are always expertly protected from damage.  Vogel and Noot - Vienna Line radiator Other makes we have fitted and found to be well made include Stelrad, Purmo, Myson and the innovative Jaga Low H20 range. Vogel & Noot, Myson and Purmo are all owned by the same group. School Radiators: These beautiful iron units are being removed in their hundreds by over zealous local authorities in schools and public buildings, and replaced with cheap and relatively short lived pressed steel units. Safety guidelines encourage councils to fit "low surface temperature" radiators (a radiator in a tin outer box) because of the 'risk of burns' from standard units. Iron school type radiators are the embodyment of sensible recycling. Refurbished school radiators are typically already 50 years old or more, and will carry on almost indefinitely. Nothing looks as classy as a refurbished school radiator in a period setting.  Refurbished School radiators We can supply and fit radiators in your choice of colour, in a variety of column depths and widths. Radiators are made up to order from reclaimed units, our supplier has over 1000 radiators in stock awaiting refurbishment at any time. School radiators are made from sectional castings, so they can be assembled to suit your requirements. Each radiator is shotblasted, assembled to size, painted and pressure tested.  Example of Hot Water & Central Heating installation in Surrey, 2008 A selection of old pattern new brass valves with bakelite handles are available to complete the job.
Imported replicas are available but the quality of the castings are noticeably inferior to the original British made units. We say buy reclaimed, and recycle our heritage. Towel Rails
Towel rails for bathrooms are usually tubular and have a low heat output for their size compared to radiators. If you have a reasonable sized bathroom it is unwise to expect a ladder towel rail to generate enough warmth on a cold day. A lttle known fact is that if you took two towel rails, identical bar the fact one is white and the other chrome, the white unit will have a 30% higher heat output. So if you need a high output towel rail, ignore the chrome ones! Bathroom towel rails are becoming a major 'user chooser' item, with a bewildering variety of designs available. We can fit your towel rail, please call for details. Manual Radiator Valves
We use the Honeywell VH200. This valve is a compact, proven design, offering great durability. Furthermore, and almost uniquely, this manual radiator valve has an easy upgrade to a thermostatic valve head at a later date, see below.  Honeywell VH200 manual radiator valve Thermostatic Radiator Valves:
The Honeywell VT200 is not a cheap product, but justifies the investment with looks, reliability and build quality.  Honeywell VT200 thermostatic radiator valve It uses the same valve base as the VH200 manual valve above. So even after installation, a customer can upgrade their manual valves for thermostatic ones, without needing tools (or plumbers). Timed Thermostatic Valves:
For some years, our customers have asked why there isn't a timed radiator valve available, that could automatically turn down the heating when not required. This type of product would have applications in most properties, for instance;
We were surprised to discover that Honeywell EU manufacture this type of valve, but it is not distributed in the UK. So Hot Water & Central Heating import them especially for our customers!  Honeywell timed thermostatic radiator valve As you might expect, the Honeywell timed radiator valve fits on the Honeywell valve body pictured earlier. It is also compatible with the popular Danfoss TRV and Drayton TRV4 bodies. Operation is simple..... You decide on a low temperature setting (eg: 12ºC) and a high temperature setting (eg: 20°C). You then tell the radiator what periods of the day, and week, those temperatures apply. These units are the most economical way to 'zone' your home heating, and save energy. They use 2xAA batteries, which last typically 2 years. Your preset temperature can be overridden at any time by just turning the blue handwheel, the temperature reverts back to the programmed routine later in case you forget. NB: for an upgrade from this, giving room by room remote control and boiler interlock, see our Hometronic page. Underfloor Heating Common on the continent for some years, and pioneered by the Romans, underfloor heating is becoming popular in the UK. Modern systems use a manifold in conjunction with a dedicated pump, linked to continuous circuits of plastic pipe under the floor.  Hot Water & Central Heating are committed to the benefits of underfloor heating... we've even installed it in our HQ in Surrey. Further examples are on our installation blog page. Hot Water & Central Heating supply and fit; - Velta Underfloor Heating Systems. - Lagerstedt & Krantz Underfloor Heating Systems   Things you should bear in mind when considering underfloor heating: Cost: Underfloor Heating is far more expensive than radiators to install, in almost all circumstances. If you are having a new subfloor constructed, or it is a new building, underfloor heating is relatively easy to incorporate at the construction stage. If it is to be retro-fitted in an existing property, the additional building works with screeded underfloor heating in terms of screed thickness and insulation will be significant. Work by other trades stops whilst the pipework is being laid, and can only recommence when the screed is safe to walk on. Benefits: Underfloor Heating in concrete slabs provides a much more comfortable living/working space. The feeling of warmth from low down, and the reflected energy from the floor, makes us satisfied with lower room air temperatures than we would accept with radiator heating. If you were to take two identical rooms, as a guide the room thermostat would need to be turned down by at least 1ºC in the underfloor heated room compared to the conventionally heated version. This lowering of temperature without any noticeable deterioration of comfort results in a typical energy saving of 10%. If you have a modern high efficiency boiler the lower operating temperatures of underfloor heating make further reductions in energy consumption due to the boiler working in 'condensing mode' for longer periods than with radiators. Finally, if you are thinking about a heat pump instead of a fossil fuel boiler, the lower temperature water used by underfloor heating gives the best Coefficient of Performance from the pump. Disadvantages: Cost of installation, particularly if the building works are just for the heating provision and not part of other renovations you were doing anyway. Having warmed a few tons of concrete up, it takes a while to cool it down again. So an unexpectedly warm or sunny day will make the property very hot indeed while the thermal mass of the floor cools down. Similarly, a sudden cold snap will result in a delayed reaction from the floor. Some types of floor covering, for instance natural wood, can suffer by fast drying and shrinkage can occur. If the floor is properly acclimatised prior to laying this should not be a problem. Is your house suitable? The most important thing is insulation. Heat from a floor can go down as well as up; houses built in the 1980s and before usually have no insulation under their concrete slabs. Underfloor heating will not work economically when laid on an uninsulated floor. The costs of either excavating to insert insulation, or raising the the finished floor level to insert it, are significant. Electric UFH versus water based UFH: Electric UFH is vastly cheaper to buy and install. It resembles a knitted electric blanket and uses a network of mains 230v heating element wires. At the time of updating this section of our site (December 2008) Natural Gas fired heating costs around 3.8p per Kwh, Electricity costs around 11.5p per Kwh. So any significant area of electrically heating floor will cost in the region of 300% more to heat, every day, for the foreseeable future. The electric UFH is often recommended and fitted by bathroom fitters, conservatory and kitchen companies because it is cheap and easy; very often there is no insulation underneath. The running costs will be very high. With electric UFH just a break in the small wires in the mat will cause a total failure. In contrast, water based UFH consists of a number of endless loops of plastic barrier pipe, which will last almost indefinitely. Finally, the heat output from water UFH is higher than electric systems. So, to summarize, the only advantage of the electric mat systems is speed and cost of the actual installation. After that, it is uphill all the way. Delay: With the screeded type, five weeks should elapse after the screed is finished before you can put significant heat through the system. The pipe must remain pressurised during the screed curing cycle. Contractors: You should choose a company with experience. 'Your builder' is therefore not usually the best choice. Builders and heating systems are generally incompatible; even if they have no idea about underfloor heating most 'will have a go'. Underfloor heating installation faults are usually buried in concrete or under expensive wooden floors, and will be very expensive to rectify. Choice of boiler: Most underfloor heating systems should not have water circulated in excess of 50 degrees centigrade. This is to prevent the screed cracking, and also to make it comfortable to walk on. This is usually achieved by a water mixing pump attached to the manifold mixing in lower temperature water from the return circuit. Some boilers (such as Vaillant units) can be programmed to restrict their output temperature, which provides an extra level of protection. Because of the low water temperature requirements when compared to radiators, condensing boilers are a particularly good partner for a screeded underfloor installation. So with a new high efficiency boiler, there is no better partner than underfloor heating. |
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