1. As a matter of general interest, what would be the final breakdown (%) in remediation cost for older house heat loss corrections due to
* Draught sealing
* Insulation
2. Draughts are part and parcel of an old house.
3. But is there not a building code to ensure draught avoidance in common areas like doors, windows, vents, etc home built since 1990s ?
1. How long is a piece of string ... define "older". Some "older" houses are far easier (cheaper) to remedy for losses due to air leakage than newer ones. For example, a 1960's semiD with suspended ground floor and rendered external walls versus a 1990's/naughties semiD with concrete floor and dry lined hollow block walls. In my experience, the return is far better, in both bang for the buck terms as well as comfort, in addressing air leakage in a targeted measured way. After all we do not live in a very cold climate (where good insulation comes to the fore) but instead live in a mild but windy one.
To put some numbers on it, I was involved recently in the upgrade of a 2 bed apartment built in the 1980's. The cost of the air tightness materials used to reduced the (measured) air leakage rate by 78% (from 10 to 2.2 m3/hr/m2@50Pa) was less than 300 euros. This was a complete gut job but I'm using it to give an example that it is possible to make a real difference without breaking the bank if a targeted approach is taken.
A consequence of this air tightness work means that the apartment can no longer rely on natural background ventilation so a specific ventilation system was required to compensate for the reduced air infiltration.
The result is a much warmer apartment, with better internal air quality than previously and yet there was no extra insulation works done.
Very easily and in the absence of a proper survey / investigation someone else could have spent say 10 grand to internally insulate the apartment (grant aided) which would have been entirely wasted if the air leakage issues were not addressed (and not to mention possibly introducing a real mould risk at the back of the insulation).
2. This is the point, they don't need to be. The majority are reasonably easy to address permanently. But you need to know where to look and how to remedy.
3. There is. It's in technical guidance document part L of the building regulations. However, it's the poor relation when compared to insulation requirements. The current criteria is for the air permeability to be less than 5m3/hr/m2 @ 50 pascals pressure difference but prior to 2008 there was no specific criteria.
Even so, lets break down the current criteria. So 5 m3 of air is allowed to pass through each m2 of envelope area (combined area of ground floor, external walls and roof) per hour at 50 pascals pressure (equivalent to a 22mph wind outside). Think about this for a minute. For a standard semiD this probably equates to a full internal air change every 12 minutes! And it was only changed from 7 to 5 m3/hr/m2 last November. For comparison purposes a passive house equivalent is approx 0.6 (over 8 times tighter than current Irish b.regs) and has been the same for the past 25+ years.
Also, rarely do windows or door make the list of top 3 issues in a typical house.
I guess the point I'm trying to make is that lack of or poor insulation in houses is generally not the big problem with heal loss from a house (new or old) especially if the house cools down quickly once the heating is turned off and the real culprit is air leakage which is fixable when understood.