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For expert advice and a professional service contact Adrian J Singleton Limited - Chartered Building Surveyors

Building Types and Key Facts to Consider

If you are looking at an house constructed before 1976 in England and Wales (or 1986 in inner London) the construction standards or 'building regulations' to give them their correct title did not deal with energy conservation.  Until that time the thermal efficiency of buildings was not an issue.  Therefore, in buildings constructed before this time there was no specific level of insulation required to be achieved in walls, floors and ceilings.  Energy costs and particularly the oil crisis of 1973 ushered in an age of conservation, although the standards introduced in 1976 are nothing like the present day ones.  Since the introduction of new format building regulations in 1985, and the constant revision to these as technologies advance, all buildings have had to meet increasingly more stringent test standards for thermal efficiency.  Without labouring the science, effectively a wall or roof is now likely to three to four times more effective at keeping the heat in than a similar wall or roof constructed between 1976 and 1984.  Homes constructed in the 21st century will also be less draughty and will have an air-tight feel about them that some may actually find unpleasant, especially in the summertime.  Ventilation, both natural and incidental, was restricted in houses from 1976 onward, but little changed until the 21st century in regard to prevention of heat loss through excess openings and designed air changes.

In fact, air is the most expensive and most inefficient thing to heat in any home.  It will cool very easily and hence the need to provide floors, walls, windows, doors and roofs that insulate as well as enclose air spaces so that the air temperature can be maintained more easily and with less continuous heating requirements.  However, you cannot completely seal up a house because the stale air will lose oxygen and gain carbon dioxide as the occupants breathe, and the air will get more humid due to the amount of water vapour naturally released by the occupants as they breeve and also when they cook and wash.  Hence in ultra-modern house design there is a growing interest in heat recovery systems that allow stale air to be exhausted from the building stripped of its heat, and that heat transferred back to the incoming fresh air.  Such systems do, however, require energy inputs to run, and there has to be a balance between comfort and energy efficiency.

Older Houses v New Homes

Quite apart from the charm and character of some older houses, many people prefer them because they tend to be more generous with room space and ceiling heights.  They often have larger windows and they look and feel substantial.  These details are often not present in newer properties, especially so called 'starter homes'.

Larger rooms have, of course, greater volume and hence more of that troublesome air to heat in winter and cool in summer.  The big windows and doors should take care of the cooling, but in winter those same elements can never be as efficient in terms of thermal insulation as any wall or roof, new or old.  So they act like a radiator panel to the outside air, moving heat out of your room faster than the adjacent walls and hence the room will cool quicker.  Although, do read on because there are advantages to be had with walls made of substantial brick or stone. 

Size Matters

If a living room in an older house is 4.8 metres long, 3.9 metres wide and 3.2m high (roughly, 16' x 13' x 11' for those who use Imperial measurements) it has a volume of approximately 60 cubic metres (nearly 2,290 cubic feet).  A modern living room for a similar house might only measure 4 metres long, 3 metres wide, and just 2.4 metres high (roughly 12' x 10' x 8') and is hence approximately 28.8 cubic metres or, in other words, for a quarter reduction in the dimensions the volume halves.  That is a lot less air to heat up.  Modern homes will heat up more quickly and once heated up will lose that heat through the walls and windows and doors and of course the roof and even now the floor at about a third of the rate it is lost in an older house.  Perversely of course, in the summer with the sun shining in, the air will be heated up much more quickly too, and the walls will release the heat much less slowly - especially of the air outside is also hot. 

Insulating an older building

You can of course insulate an older property and vastly improve its thermal performance as a result, but the techniques for this all have their drawbacks and no one solution is suitable for all building types.  I did mention that there are advantages to walls made of substantial brick or stone.  Although they are not as effective at insulating, they do tend to cool down much slower and hence rooms so enclosed often have a more stable temperature over a longer cycle.  As the air is warmed up it also starts to warm the bricks and stones.  Eventually they will dissipate that heat out to open air, but cut the heating inside the room for a few hours and the temperature takes a while to significantly fall.  This effect is exactly the same as the concept used in electric storage heaters, were night time electricity is used to heat up bricks to a rather high temperature and then they continue to dissipate heat throughout the day into the room even though the power has been switched off.

To really benefit from the storage effect of brick or stone the reflective part of the insulation needs to be on the coldest side and hence, in theory, external cladding is the best form of insulation for such buildings.  However, there is a thing called 'interstitial condensation' that occurs as warm moist air cools to a temperature where it cannot support the water vapour and the vapour liquefies as water droplets or 'dew' on the surface of anything colder.  The exact temperature at which this happens is influenced by a number of factors, but the 'worst case scenario' can be calculated scientifically and it is this that will determine where the 'dew point' will most likely occur.  This is often within the thickness of the brick wall and as such is likely to cause penetrating dampness and mould.  To overcome this, a vapour check such as foil backed plasterboard can be used on the warm side of the wall to prevent the moisture being transmitted through the wall.  The nett effect is to make all the walls much thicker, with a small reduction in room size and a change of appearance outside.  This is, of course, providing you can get planning permission to put the cladding on in the first place.  Assuming those hurdles are overcome, you can benefit most from the storage effect of the bricks protected from heat dissipation by external insulation provided that you heat the building up and then maintain the heating at a fairly constant temperature.  This means running the heating 24 hours a day, but after the initial charge up the heating will tick over gently to just top up the gradual loss inevitably made through air changes, and through the insulation itself.

But all of that is a very big task and best suited to a full scale refurbishment and possibly remodelling of a house.  It is not something that a regular home buyer should or could consider as a viable proposition for a house that is being bought as your one and only home.  For an investor, however, the attraction is that all the faults of the older building can be tackled at the same time and a 21st century standard of thermal performance can be applied to a classically designed property, albeit it might even be cheaper to knock the old one down and start again!

Getting professional advice

If you want your chartered building surveyor to assess whether your intended new home could be economically enhanced in terms of its thermal performance, ask for it as part of the services you agree on.  If you asked for this from Adrian J Singleton Limited for instance, the seller's Energy Performance Assessment will be examined and sense made of the suggested rating improvement stated on the assessment.  It might well be that the existing property is rated as low as G but the assessor indicates it can be brought up to E or even D, but at what cost?  That is the bit that such ratings cannot easily reveal.  And what is to stop you getting an even higher rating?  What Adrian J Singleton Limited and similar firms can do is evaluate the building and give you an idea of the cost of each form of thermal efficiency improvement you can make to the property, and then you can judge for yourself whether the additional outlay will ever be worthwhile to in terms of the savings made in running costs over a reasonable number of years and the potential effect on the resale value by having a more energy efficient home to offer to a new buyer in the future.

Time is of the essence

It has again to be stressed that if you want the best advice you have to give it time to be formulated.  A full energy review can take two or three weeks to be completed after the building is surveyed and measured, the systems for improvement evaluated and the report compiled.  So if energy bills are an important consideration for you in deciding on your new home, you should get your surveyor appointed nice and early if you are to have any chance of being able to control the seller's eagerness to sell to anyone offering the best price with no questions asked.  When the housing market is strong time is a vital consideration and a rushed review is less likely to give you a definitive answer on whether your intended home is suitable for improvement.

Caveat emptor

That term has a habit of popping up at unwelcome times.  Rushing the purchase just to avoid being gazumped is sometimes a harsh reality in the house buying process, but if you line things up properly then even in a strong market your professional team can help you get a feel for whether you can achieve your ambitions on energy reductions as well as finding the home ideal for so many other reasons for you, the home buyer.

Let's get back to finding a new home!

 

Last updated 28th September 2012

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