Ravenswood Ranch
A 1958 ranch with a gas bill of $340 in January and a contractor who had quoted a heat pump without opening a single wall.
$146,900Contracted and paid
11 weeksOn site
On timeAgainst the contracted date
2026Chicago, IL
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Survey to close-out, in the owners' own sequence.
The brief
A 1958 ranch with a $340 January gas bill and a heat pump quote from another contractor that had been written without opening a single wall.
What the survey found
A borescope into three cavities found nothing in the north wall at all. A heat pump sized against that house would have been sized against a hole.
What we did about it
Cavity fill, rim joist sealed, attic to R-60, airtightness tested before and after, and only then a heat pump — two sizes smaller than the original quote, commissioned and balanced rather than switched on and left.
“The first January after: $121, on a colder month than the one that produced the $340.”
Eleven weeks, measured at both ends.
A blower door before and a blower door after, with the January bill as the third measurement. Every entry in this log has a number attached to it.
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Day 1
Survey
Borescope into three cavities. The north wall had nothing in it. A heat pump sized against that house would have been sized against a hole.
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Week 2
Model
Measured heat-loss model built before any equipment was specified, so the plant could be sized to the house we were going to leave behind.
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Week 5
Envelope
Cavity fill, rim joist sealed, attic topped to R-60. Airtightness test before and after, both numbers in the handover pack.
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Week 9
Plant
Heat pump two sizes smaller than the original quote, commissioned and balanced rather than switched on and left.
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Week 11
Close-out
On date. First January bill after the work: $121, on a colder month than the one that produced the $340.
The bill went from $340 to $121.
Envelope first, plant second. If your January bill looks like the first number, the survey will tell you which wall is costing you it.