Swamp cooler to refrigerated air, start to finish.
Written to be read before you get any quotes at all — including ours. If you only take one thing from it, take the part about return air.
Why it is a project
Two machines that do almost nothing alike.
People expect a conversion to be a swap. It is not, and the reason is worth two minutes.
An evaporative cooler is a one-way flow. It pulls outside air through a wet pad, pushes a very large volume of it into the house, and the house pushes the old air out through an open window or a relief vent. Nothing comes back. The duct, where there is any, is sized for that big one-way volume.
Refrigerated air is a closed loop. It takes indoor air, cools it, and puts it back — a smaller volume, moving faster, through a sealed system that has to collect the air again at the other end. The house stays shut.
So the two systems want different duct sizes, different layouts, and — the part that catches everybody — a return path that a cooler house simply does not have.
The opening a roof cooler leaves, framed and decked
The five pieces
What a real conversion quote contains.
If a quote you have been given does not have all five of these on it somewhere, the missing ones have not gone away — they have just not been decided yet.
One · Equipment
Outdoor unit, indoor unit, line set, thermostatThe part everybody quotes, and often the only part on a cheap quote. Sized to the house rather than to a rule of thumb — and in these tracts the rule of thumb has historically been too big.
Two · Supply duct
New runs to every roomIn a cooler house this is new work, not a modification. The existing cooler duct is the wrong size, usually the wrong shape, rarely insulated to today's standard, and laid out to dump air into a hallway rather than to serve individual rooms.
Three · Return air
The half nobody mentionsThe system has to get the air back. A cooler house has no return path at all, so this means a return plenum, one or more grilles sized properly, and a way for air to leave closed bedrooms — transfer grilles or undercut doors. It is a real part of the cost and it is where cheap conversions go wrong.
Four · The roof
Cooler out, curb out, opening framed, decked and made watertightPriced with the job. A roof-mounted cooler leaves an opening with framing cut around it. Somebody has to close it, and finding out on the last afternoon that nobody agreed to is a bad way to end a project.
Five · Permit and disposal
Pulled by us, inspector met by us, old cooler taken awayAnd if the electrical panel needs work, that is your electrician's line — flagged on the first visit and in your budget from the start, not discovered in week three.
The electrical question
A cooler draws almost nothing. This does not.
An evaporative cooler is a fan and a small pump. It runs happily on a circuit that was put in when the house was built.
A refrigerated system needs a dedicated circuit with real capacity behind it, and a fair number of the houses we work on here still have a small service with very little spare. That is not a defect; it is what was appropriate for a house heated by a wall furnace and cooled by a cooler.
We do not do panel work. We check the panel on the first visit, tell you what the equipment will need, and say plainly whether an upgrade is likely. If it is, that is your electrician's cost and it belongs in your budget from day one. It is one of the two things that most often turns a comfortable project into an uncomfortable one.
The other is the roof.
Checked on the first visit, every time
Keeping the cooler
You can have both. Two conditions.
Condition one — the relief path must close
A cooler needs an opening for air to leave the house. When the cooler is not in use, that opening is a hole in your ceiling connecting the conditioned house to the attic, all winter and all through every afternoon you run the air conditioning. It has to have a damper that genuinely seals, and somebody has to be willing to operate it.
Condition two — they must never run together
A cooler pushing outside air into a house that a refrigerated system is trying to keep closed and dry is the worst of both: you pay to cool air that is leaving through a hole in the ceiling, and you add moisture to a house you are paying to dry out.
Some people want to keep the cooler for the dry part of the season, and there is a reasonable argument for it — it is cheap to run and it moves a lot of air.
But it only works if the house can genuinely switch between two modes, and that means the damper and the discipline. If nobody is going to manage it, one good system is a better outcome than two half-used ones, and we will say so.
If you are removing the cooler entirely, say so early. It changes the roof work, it changes where the return can go, and it occasionally changes where the indoor unit is best placed.
Supply where the cooler once dumped into a hallway
Warning signs
Four ways these jobs go wrong.
Each of these is visible in a quote if you know to look, and each one is the reason somebody ends up with a project that costs half again what they were told.
Warning one
"We can use your existing ducting"
Occasionally true in a house that once had a ducted furnace. Almost never true of cooler ducting. Ask what size the runs are and how many returns the design has; if the answer is vague, the price is a placeholder.
Warning two
No return air on the drawing
If the quote lists supply registers and nothing about returns, transfer grilles or door undercuts, half the airflow design is missing. This is the single most common omission and it produces a system that is loud, uneven and never quite gets there.
Warning three
The roof is somebody else's problem
Ask directly: who frames the opening, who decks it, who makes it watertight, and is it in this number? If the answer is "you will want a roofer for that", you are being quoted for part of a project.
Warning four
Nobody looked at the panel
If a quote for a conversion was produced without anybody opening the electrical panel, the electrical requirement has been assumed. In this housing stock that assumption is wrong often enough to matter.
And one more, about us
Our conversion quotes are sometimes higher than the first one a customer got, and this page is the reason. If you have a cheaper number in front of you, take these four questions to whoever wrote it. If they have good answers, use them — genuinely. If they do not, you now know what the difference was.
Conversion questions
Asked once people have read this far.
How long does a conversion take?
It depends almost entirely on the ductwork, which depends on the attic. What we will not do is give you a number on this page and then a different one at your house. On the survey we give you a day count in writing, and the roof is always closed the same day it is opened — that is the part we will not let run over.
Do I have to move out?
No. It is dusty and it is noisy, and there will be a day when the power to part of the house is off while the electrical work is done. Most people stay. Where somebody in the house needs the dust kept down for a health reason, tell us at the survey and we will plan the sequence around it.
Can you do it in stages to spread the cost?
Sometimes, and the sensible split is ductwork first and equipment second, not the other way round. Duct is the part that has to be right and the part that is hardest to change later. What does not work is putting equipment in now and promising yourself the returns next year — that is how a system ends up permanently underperforming.
Will a heat pump work here instead of an air conditioner and a furnace?
Yes, and a conversion is the natural moment to consider it, because you are putting in a duct system anyway. Winters here are mild, which is the condition heat pumps handle best. We will raise it on the survey, we will price both, and we will not attach a savings figure to either.
What if my house already has an old ducted furnace?
Then you may be in a much better position, and the first thing we do is find out whether that duct is worth keeping. Some of it usually is. That changes the quote substantially, and it is the one scenario where a conversion comes in a lot cheaper than people expect rather than a lot dearer.
Get the survey before you get the quotes.
An hour in the house, no obligation, and you leave with the five lines filled in — whether or not you use us.
