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A house with more people in it than it was built for
Most of Downey was drawn for one family and one shift. A lot of it now holds three generations and somebody is always home. This page is about what that does to a system that never changed.
The system was designed around assumptions that stopped being true. A house sized in 1957 assumed a certain number of people, in certain rooms, at certain hours, with a garage that held a car. When the household grows, none of the equipment changes — but which rooms have to work, and when, changes completely.
Almost none of the fixes for this are equipment. The useful ones are balancing, return paths, duct repair and a schedule that matches when people are actually in the house. They are cheap, they are boring, and they are rarely offered because nobody makes much money from them.
We start with what is free. In most of these houses the free answers have never been tried, and on a fair number of visits that is the whole job.
Pick what is happening and what you can realistically change. Everything below is written out in full.
Open every register and look behind the furniture. A bed, a sofa or a chest of drawers over a floor register, or a wardrobe in front of a return, is the commonest free fix in this town. Air that cannot get out of a grille is not cooling anybody.
Check the damper handles. Most of these houses have manual dampers in the attic ducts, set once, decades ago, for a household that no longer exists. Turning two of them is free and can move a genuinely useful amount of air from a room nobody uses to a room somebody sleeps in.
Leave interior doors open, or undercut them. A closed bedroom door with no return path means air cannot leave, so it will not come in. If the door must be shut at night, an undercut of an inch is a carpenter’s ten minutes and it changes that room.
Change the filter, and check it fits. Not the grade — the fit. A filter rattling loose in a rack is letting air go round it.
Set the thermostat for when people are actually home. A schedule written for an empty house and a five o’clock return is wrong in a house that is occupied at two. Holding a steadier temperature usually costs less than recovering hard every afternoon, and it is far more comfortable.
And use the fan setting. Running the blower continuously, or on a circulation setting, evens out temperatures between rooms at a cost of very little. It is the single most useful free change in a house with one thermostat and six people.
One room is always wrong for the person in it
The commonest call we get, and it is almost never the machine. If the rest of the house is comfortable, the system is working — the air is simply not arriving where it is needed, or not leaving.
Four causes, cheapest first. Something over the register. A damper set for a different household. No return path, because the door is shut all night. Or a duct problem — crushed flex, a disconnected boot, a run that was always too long.
The fifth, which people forget: the room may genuinely be harder than the others. A west-facing bedroom with a lot of glass, a room under a thin patch of attic insulation, a room over a garage. Those are real and they do not go away with a damper.
A measurement at that register, compared against another room, settles which in about twenty minutes. That is the visit worth booking, and it is not a replacement quote.
The bills went up when the household grew
Some of that is unavoidable and worth saying plainly: more people, more hours occupied, more cooking, more hot water and more equipment all cost money. Nobody can make a house with six people in it as cheap as a house with two.
But a good part of the rise is usually avoidable, and it is rarely about the equipment’s efficiency.
The hours. A house occupied at two in the afternoon is being cooled through the hottest part of the day, which it was not before. That is a real change and it makes the duct leakage in your attic matter far more than it used to.
The recovery. Letting a house get hot and then pulling it back down hard is more expensive than holding it steadier, and it is much less comfortable. A schedule written for the old pattern is now working against you every day.
And the rooms. If the system is cooling the whole house to satisfy one bedroom that never gets there, you are paying for five rooms to fix one. That is a balancing problem wearing a billing costume.
We will not give you a percentage for any of this. What we will do is measure the duct, look at the schedule and tell you which of the three is costing you most.
You are cooling rooms nobody is in
A reasonable instinct, and the usual response — closing the vents in unused rooms — is the one thing worth being careful about.
Closing registers does not save what people think. The blower still moves against the system, and closing several raises the pressure it works against, which reduces total airflow, makes the system less efficient and can push more air out through duct leaks. Closing one in a six-register house is fine. Closing three is working against yourself.
What does work. Balancing with the dampers in the ducts, which is a different thing from the register face and is done at the branch rather than the room. Closing the door to a genuinely unused room, with its register partly rather than fully closed. And, where a part of the house is consistently unused, considering whether it should be on its own system at all.
One warning. A closed-up room in this climate still needs some air movement. A sealed room with no circulation gets stale and, in a damp winter, can get damp. Partly closed rather than fully closed is the rule.
Somebody is home all day now
This changes more than people expect, and almost none of it is about the size of the system.
The schedule is now wrong. A programme that lets the house drift from eight to five was written for an empty house. Left alone it means somebody sits through the hottest hours in a house that is deliberately not being cooled, and then the system works hard from five. Both halves of that are worse than simply holding a steadier temperature.
The thermostat is in the wrong place for the new pattern. It was probably fine when the house was empty all day. If the person at home spends the day in a back bedroom and the thermostat is in the hall, the house is being controlled from a room nobody is in.
And comfort expectations differ. An older parent frequently wants a different temperature from a teenager, and in a one-thermostat house that is a real conflict that a machine cannot solve. Balancing helps, a separate system for one room helps more, and there is no setting that satisfies both.
That last point is worth being honest about rather than pretending a new system will fix it.
A converted garage or an added bedroom
The hardest room in the house, and the one most often tied into the existing system with a single small run and a hope.
Why it is hard. A converted garage has an uninsulated slab, a wall that used to be an exterior wall, and frequently a roof with very little above it. An added bedroom on the end of the house has more exterior surface than the rooms around it. Both take more to condition than their floor area suggests.
Why extending the system usually disappoints. The plenum was sized for the old house. A new branch off it takes air from the rooms that already had it, so the new room is mediocre and everybody else is slightly worse. And there is usually no return, so air cannot leave.
The answer that works. More often than not it is a separate ductless system for that space: its own capacity, its own control, and no effect on the rest of the house. It is a smaller job than a system replacement and it solves the problem instead of spreading it.
Nothing that costs money
See the list above, which is the substance of it. Two things to add.
Try one change at a time and give it a few days. Changing the schedule, the dampers and the fan setting in one afternoon means you will never know which one helped, and one of them may have made things worse.
And if none of it works, that is information too. A house where every free change has been tried and one room is still five degrees out has a physical problem, and you can say that to anybody who visits rather than being talked through the basics again.
Dampers, registers and small work
This is where most of these houses should be spending, and it is the least likely thing to be offered.
Proper balancing means measuring what each register delivers, adjusting at the branch dampers rather than the grilles, and measuring again. It is a couple of hours and it redistributes what you already have to the rooms that now need it.
Return paths are the other half. Door undercuts, transfer grilles or a new return in the room that is worst. Cheap, and frequently the single biggest improvement in a house with bedroom doors shut all night.
And targeted duct repair. One crushed run or one disconnected boot can account for an entire room. Fixing that is an afternoon, not a project.
Together these cost a fraction of equipment and, in a house whose use has changed rather than whose equipment has failed, they are usually the correct answer.
You could add a separate system
Worth considering seriously, and worth doing in the right order.
Do the balancing first. If the existing system can be made to serve the rooms it was built for, then a second system only has to handle the space that was added — which makes it smaller, cheaper and easier to place.
Where it makes most sense: a converted garage, a room over a garage, an added bedroom, a room used at completely different hours from the rest of the house, or the room of somebody who wants a different temperature from everybody else. That last one is a legitimate reason and people are often embarrassed to say it.
What to think about before agreeing. Where the outdoor unit goes and how close it is to your neighbour’s window. The electrical capacity. And whether a multi-zone system covering two or three rooms is better than a single one — usually it is, if you can see the second room coming.
You are replacing soon anyway
Then this page matters more, not less, because you are about to fix the answer for fifteen years.
Size it for the house as it is used now. More people is more load, but it is a smaller number than most people assume — a few hundred BTU per person. The bigger factors are the added space and the hours the house is occupied. Both belong in the calculation and both are things you have to tell whoever does it.
Do not let the duct come along unchanged. New equipment on the same unbalanced ductwork will reproduce the same complaints faithfully. This is the one moment when the incremental cost of putting it right is smallest.
And ask about zoning or a second system at the same time. Not because it is always right — it often is not — but because it is far cheaper to decide now than to add later.
What to do next
Move whatever is in front of the register, open the door at night for three nights, and see what changes. If nothing does, book a measurement at that register rather than a replacement quote.
What to do next
Change the schedule to match when people are actually home, and get the duct leakage measured. Those two account for most of the avoidable part. Ignore anybody offering you a percentage.
What to do next
Stop closing registers fully, and get the branch dampers balanced instead. Closing several grilles raises the pressure on the system and costs you more than it saves.
What to do next
Rewrite the schedule for the new pattern and look at where the thermostat is. Holding a steadier temperature usually costs less than recovering hard every afternoon, and it is much more comfortable for whoever is there.
What to do next
Have the added space assessed as its own load, and ask specifically whether it should be on the existing system at all. The answer is frequently no, and the alternative is cheaper than a replacement.
What we will not do
We will not tell you a bigger system fixes a distribution problem. If one room is wrong and the rest of the house is fine, capacity is not the missing thing.
We will not pretend one thermostat can satisfy everybody. In a house where people want genuinely different temperatures, balancing helps and a separate system helps more, and no single machine solves it. Saying otherwise sells equipment and disappoints families.
We will not print a percentage for any saving, because it depends on your house, your summer and how many people are in it.
And we will happily do the free visit and leave. If the answer is a damper handle and a door undercut, we will say so, and there will be nothing to sell you that day.
The measurement, not the quote
A visit, the registers measured in the rooms that matter, the duct checked, and a written note of what we would change in what order — starting with the parts that cost nothing.