Limpsfield is a village on the outskirts of Oxted, Surrey (UK).
View from the road
Our customer already has a ‘Hot Water & Central Heating’ installed oil fired cooker range (see our Heritage cooker page above), and was building an outside barn further down the garden.
The central heating boiler was an old oil fired unit, which was located in the hallway and could be heard throughout the property.
Our customer wanted a new boiler and also wished to convert the water system to a new unvented type.
Hot Water & Central Heating suggested that a Grant 3646 outdoor module was fitted, this is an outdoor boiler incorporating a weatherproof housing, designed to operate outside in all weathers.
Grant Vortex condensing high efficiency outdoor boiler module
This freed up the cupboard in the hall, previously home to an oil boiler and a small vented hot water cylinder on braces above. We removed these units and replaced them with a Range Tribune Slimline 210 litre unvented cylinder. This upgraded the hot and cold water to mains pressure at all outlets, and removed the need for a loft mounted storage tank.
Range Tribune unvented installation in cupboard
In common with all unvented systems (and other forms of direct fed hot and cold water systems, like combination boilers and heatstores) the performance is greatly improved with a good water flow rate. We ran a new 32mm water pipe to the road outside, for minimum hydraulic resistance. The local water supply company were engaged to provide a new larger connection to the mains.
New water connection being excavated by Sutton & East Surrey Water
The new oak barn was home to a sun room, together with a utility room and shower room. Hot Water & Central Heating installed underground pipe ducts to the main house to give hot and cold services, and also to feed the new underfloor heating.
New oak barn
Underfloor heating manifolds are quite large units, and it is prudent to site them where inspection and maintenance is easily carried out after the building works are complete. This ruled out fitting the manifold under the sink or behind washing machines. Instead, we installed a 7 zone L&K manifold in the ceiling void area above the utility room, hiding the pipework in a stud wall comprising part of the new shower enclosure.
Underfloor installation waiting for screed
The L&K system used nearly 500 metres of pipe, all laid on Building Regs compliant Quinn insulation board. The Underfloor Heating was laid in a day, and the concrete screeding completed the day after. The flooring will be finished in tiling once the screed has properly dried out.
Another view of the underfloor pipework
Heating manifold hidden in ceiling area
Screed laid, all pipework buried. This area will be tiled soon.
Separate zone controls were fitted for the underfloor area, which were linked by armoured cable buried in a duct to the existing house. Control of the separate heating zones is by Honeywell CM series programmable room thermostats.
Underfloor heating is an invisible but highly effective system*, and uses less energy to heat a space than conventional radiators. This is because the human body feels warm at lower air temperatures when using underfloor heating.
The new boiler works at around 92% efficiency, saving fuel but increasing comfort and reliability. In common with all our Grant boiler installations, our customer received a 3 year on site warranty on the boiler.
*The only type of underfloor heating to be avoided is the electric type, because electricity costs around 12p per Kwh, compared to around 4.5p for gas fired heating and 6p for oil fired (this was written in June 2009).
Don’t be fooled by sales literature claiming electric heating is 100% efficient and green, these are half truths. Electrical heating uses energy generated by (usually) coal or gas in the UK. From the power station to your house meter box, around 55% of the energy in the gas or coal burnt at the power station is lost in generating and transmission losses.
So before even fitting underfloor heating, electricity is only 45% efficient. And that generating efficiency partially accounts for the frightening price. So a sales person could say electric heating is 100% efficient, but it would be a half truth. If they said it was cheaper than gas or oil fired heating, it would be a lie. The only electric heating that is efficient in comparison is using a heat pump, but that is addressed elsewhere on this web site.
