Maine Coast Home Design

We all know that the better we insulate our homes the less we spend on energy for heating to maintain comfort levels… or maybe not?

Its not just insulation that saves energy in our homes it’s the overall building fabric that counts – the type of construction used, the type of windows and external doors, the levels of insulation in the floors, walls and roof – and very importantly the levels of air tightness.

Up to 1976, the primary concern when house building in Ireland was to keep out water. There was no measure required for this, as it would be immediately evident when there was a problem. In 1976 the first building regulations dealing with energy efficiency in domestic houses came into effect. The most recent regulation revisions were in 2008.

It’s interesting to see how our 2008 u-value standards in Ireland compare to Sweden. Don’t forget, lower is better.

Building Element                                   Ireland                          Sweden

Windows & Doors                                2 W/m2K                     1.3 W/m2K (35% better)

Walls                                                    0.27 W/m2K                0.18 W/m2K (33% better)

Ground Floor                                       0.25 W/m2K                0.15 W/m2K (40% better)

Pitched Roof                                        0.22 W/m2K                0.13 W/m2K (41% better)

In today’s environment with the introduction of new building technologies and greater awareness of the need for energy efficiency we should strive to design and regulate to the most demanding insulation standards. Taking the above figure for windows and doors, the maximum elemental u-value in Ireland for external windows, doors and roof lights is set at 2.00W/m2K when in fact modern windows can be sourced with u-values as low as 0.7W/m2K. The regulations in Ireland make it very easy to comply, and should therefore be seen as completely inadequate.

Is it surprising that in Ireland we are among the highest consumers of energy for home heating in Europe? What happens when oil doubles or triples in price? Have you stress tested the financial impact of this on you?

Over the last 10 years when the Celtic Tiger economy was roaring the building industry by and large, lacked the motivation, the proper building control procedures and the technical competence to consistently deliver actual insulation performance that complies with our modest standards. The policing of this was also virtually non-existent.

As the saying goes – “what gets measured gets done”. In the case of home extensions the only building performance characteristics generally consistently delivered were structural soundness (the measure of failure being subsidence and buildings falling down!) and good water proofing and damp proofing (the measure of failure being visible leaks and dampness).

The use of adequate insulation and air tightness products, and the necessary installation expertise when these works were being carried out, was vastly below the standard required, and the shortcomings were simply paid for in the monthly energy bills of the unfortunate homeowners.

Scientific testing done on existing housing stock has shown the measured (actual) u-value of a block built partial fill insulated cavity wall to be up to twice the calculated (theoretical) u-value, or losing double the heat energy expected by calculation! This is principally because of cold bridging (through concrete lintels above window and door openings for example), and thermal looping (warm air convection between the inner leaf and the cavity insulation where the insulation is poorly installed).

The internet has made the world a very small place and provides information at the touch of a button. Educate yourself a little, and demand a lot more of your architect and builder. Demand that you get what the Swedes, the Danes, the Germans, and much of Europe already have. There was never a better time to demand!

To conclude, if you are in the market for building a one off house or adding a new home extension you should ask your builder, architect or designer the following questions.

What type of insulation is in the floor, walls and roof?

Have u-value calculations been done for the floor, walls and roof?

If so can you show me a report of these calculations and the results?

What measures have you got in place to combat air permeability?

If your builder, architect or designer can answer all the above questions comfortably and shows an appetite and enthusiasm for your challenge of good U Values and levels of air tightness, and even suggests improvements then you are on the right track!