When we
bought out house loft insulation had only 25 mm loft insulation thickness, with
recommended 275-300 mm of fiberglass. I
decided to do put some more, while also use it as an opportunity to clean up
the dusty loft (no storage there).
With the
current insulation in winter our second floor was colder than first floor due
to roof loft heating losses. Additionally, I was encouraged by perceived saving
due to improved insulation.
How to calculate economic effect from
insulating your loft and any potential energy savings?
Previous
insulation – 25 mm, new – 275 mm. I decided
to use mineral fiberglass insulation, although if I do it again I would use more
expensive natural wool. Advantages of natural wool: it absorbs condensed water
and then evaporates it, traps any gases and contamination (i.e. breathes), does
not loses thickness when gets wet with condensed water. Disadvantage: more expensive, perhaps more flammable.
Materials
I used for the loft insulation:
Diall
Loft insulation – 23 rolls - 290 GBP -3m2 per pack, coverage - 68m2.
Gardman
Bubble Greenhouse Insulation - 6 rolls - 99 GBP (as a vapour barrier).
Knauf
Eko Roll Loft Insulation – 14 rolls - 280 GBP – 5.5m2 per pack – coverage - 77m2.
Loft
Vent Trays (plastic) – 40 pieces – 60 GBP.
Total
cost: 730 GBP or 10.2 GBP/m2
Additionally,
I used this as an opportunity to apply some teak oil to the joists and the roof
beams, to preserve and protect them - 20 L at 160 GBP. No installer will do
that for you, unless you specifically ask and pay.
All
together it took 5 days ~ 7-8 hrs each or 40 hrs.
How I
calculated the economic effect and return on the loft insulation:
