It met code
The equipment in a tract home was legal, inspected and signed off. Nobody cheated. It was specified to meet the requirement at the lowest cost, because in a builder's budget that is what it is for.
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Valley heat & new homes
Why a house built in the last twenty-five years in Chino, Eastvale or Ontario behaves the way it does in August — and what actually fixes it.
One
The temperature stack
On a 105°F afternoon in the Chino valley, the air outside is not the hardest number your system is dealing with. It is the coolest one in the chain.
A dark roof in direct sun runs far above ambient. The attic beneath it follows. The ducting runs through that attic, so the air inside the duct picks up heat on its way to the room. And the upstairs ceiling is the underside of all of it.
- 105°F Outside air — the number on the forecast
- 150°F+ Attic air above the insulation, mid-afternoon
- 160°F+ Roof deck and sheathing in direct sun
These are the physics, not a survey of your house
Attic and roof temperatures vary enormously with roof colour, ventilation, insulation and orientation. The point is the direction: the space your ductwork runs through is far hotter than the outdoor air, and everything downstream of that is affected by it. What your house actually does, we measure.
Two
The upstairs problem
This is the single most common complaint in this valley, and it is almost never an equipment fault.
A great many two-storey tract homes were built with one system, one thermostat, and that thermostat in the downstairs hallway. Heat rises, the upper floor sits under a superheated roof, and the system stops as soon as the downstairs hallway is satisfied. The bedrooms are still well above the set point when the compressor shuts off.
Replacing the equipment does not fix this. A bigger unit cools the downstairs faster and therefore shuts off sooner, which can make it worse.
- Airflow first
- Measure before assumingStatic pressure, airflow at each upstairs register, and the return size. A great many upstairs floors are simply not receiving the air they were designed to receive.
- Balancing
- Damper and register adjustment to push more of the available air upstairs, measured before and after. The cheapest fix, and sometimes enough on its own.
- Returns
- Usually the bottleneckAn upstairs with one small return cannot move air regardless of how much is being supplied. Adding or enlarging a return is frequently the fix that finally works.
- Zoning
- Motorised dampers and a second thermostat, so upstairs and downstairs can call for cooling independently. More involved, and the right answer where the house genuinely has two different loads.
- A second system
- Occasionally the honest answer on a larger house. We will say so, and we will say so after the cheaper options have been measured rather than instead of measuring them.
Three
Ducts in a 150° attic
Your ductwork runs through the hottest space in the building. That has two consequences, and most homeowners have only ever been told about the first.
- Leakage
- Air you paid to cool, delivered to the atticDisconnected boots, loose collars, a plenum joint that was taped rather than mastic-sealed. Every one of those is conditioned air going nowhere useful.
- Heat gain
- The part nobody mentionsEven a perfectly sealed duct picks up heat along its run through that attic. Air that left the coil cold arrives at the far bedroom noticeably warmer, and the longest run is usually the one serving the room that is already the problem.
- Return leakage
- A leaking return is worse than a leaking supply: it pulls 150°F attic air, dust and insulation fibres directly into the system, upstream of nothing.
- What we do
- Test, seal at the joints and boots, upgrade insulation on the runs that need it, and replace what is beyond saving. Priced separately so you can see exactly what it is worth.
Four
Builder-grade, explained without the outrage
There is a version of this argument that is just a sales pitch. Here is the version that is actually true.
It was installed fast
Tract construction runs on schedule. Ducting gets installed quickly across many houses, and the difference between adequate and excellent is time nobody had.
Then it met this climate
Minimum-specification equipment, on quickly-installed ducting, in a 150°F attic, running five months a year. Twelve to fifteen years is a normal life out here. It is not a scandal; it is arithmetic.
Which makes the replacement an opportunity
When that system finally goes, you are no longer buying what a builder chose. That is the moment to size the equipment to the house, fix the ducting, deal with the return, and solve the upstairs problem — all at once, while the system is open anyway. Doing it later, separately, costs more.
Five
What to fix first
If you are not replacing anything yet, this is the order we would spend money in on a typical valley house.
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Measure
Static pressure, register airflow upstairs and down, temperature split. An hour, and it tells you which of the following actually applies.
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Seal the ducts
Usually the best value on the list. Cheaper than equipment, and it makes whatever equipment you have work better.
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Fix the return
If the return is undersized, everything upstream of it is being wasted. This is where the upstairs problem is most often solved.
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Then consider equipment
With the duct system sorted, the equipment decision is a real decision rather than a hope.
The one thing we will push back on
If you call us in August wanting a bigger unit because upstairs is hot, we will ask to measure the airflow first. Oversizing is the most common mistake in this valley and it makes the upstairs problem worse, not better — a larger system satisfies the downstairs thermostat faster and runs for shorter periods.
Find out which one applies to your house
An hour of measurement, and a written answer.