HVAC FAQ: answers to common AC questions

Start with age: most systems in Central Florida are done between twelve and fifteen years, because they run most of the year. After that, watch for a pattern. The usual signs are a second big repair in two summers, rooms that never catch up on a hot afternoon, bills climbing while the thermostat setting hasn't moved, a unit on R-22 refrigerant (which is no longer made), and a compressor that trips the breaker on start. One sign on its own usually means a repair, but three of them together mean it's time to talk about replacement.

No, a bigger unit is usually worse. An oversized system cools the air fast and shuts off before it has pulled the moisture out, so the house hits 74 and still feels damp. It also short-cycles its way to an early failure. An undersized unit runs all afternoon and never catches up. The right size comes from a load calculation that looks at square footage, insulation, the windows and which way they face, the duct runs and how the space is used. The size of the old unit is a useful clue, but it can't give you the answer on its own. Houses get insulated, rooms get added, and plenty of old units were the wrong size to begin with.

A like-for-like changeout on a house is usually a day: the old system out in the morning, the new one set, connected, charged and running by the afternoon, with the house without cooling for most of that day. Add ductwork, a new line set or electrical work and it's two. A rooftop unit on a commercial building is a crane and a morning. A changeout needs a mechanical permit in Florida, and the inspection comes after; the system runs in the meantime.

Usually, and the older the current one, the bigger the gap. Efficiency ratings have climbed for years, so a new system does the same cooling on noticeably less power than one from the mid-2000s, and it's sized to the house rather than to whatever was on the truck that day. Two cautions: the saving depends on how much you run it and what you pay per kilowatt-hour, so we don't promise a percentage; and a new unit on leaky ducts throws part of the gain into the attic. We look at both before we quote.

Once a year at the least, before the summer, so a weak capacitor or a low charge is caught in April instead of on the first 95-degree day. In Central Florida the unit runs most of the year, so a second look in the fall is worth having. A plan puts those visits on the calendar so nobody has to remember; a one-off tune-up is the same checklist, booked when you think of it.

Spring, before the first stretch of 90-degree days, so a weak part is found while the weather is still forgiving and the schedule is still open. In Central Florida the unit then runs hard through October, so a second visit in the fall, before a heat pump switches over to heating, is worth having. The worst time is July: the part fails then, the phones are full then, and the house is hottest then.

A standard one-inch filter every month through the summer and every two in the cooler months; a thick media filter in its own cabinet every six to twelve. Pets, a house under renovation or a family with allergies shorten all of those. Hold it up to the light: if you can't see through it, it's done. A loaded filter is the cheapest problem an air conditioner can have and the most common one we find.

A tune-up is a single visit that you book when you think of it. A plan puts the visits on a calendar, once or twice a year for a home and on a schedule set for each property for a building. Plan members also get priority when the season fills the phone, and a discount on repairs. The checklist is the same either way, but with a plan nobody has to remember to book it.

No, anyone can call us for a repair. A plan is for people who would rather have their equipment checked before it fails than after.

You call the same number as always, and you hear back within the hour. Emergency calls are answered until 11 PM. Because the unit is on file, the tech starts with what we already know about it.

The plan is the scheduled visits and the checks that go with them. If a visit finds something that needs a repair, plan members get a discount on it, and you get the number in writing before any work.

Indoor humidity should sit between 45 and 55 percent. Above 60 the house feels clammy at 74, towels never dry and mold gets what it needs to grow. Below 40 is rare here outside a cold snap. A properly sized, properly charged system holds the range on its own for most of the year. The trouble comes in spring and fall, when the air is wet but not hot and the system doesn't run long enough to dry it. That's when a whole-house dehumidifier earns its place.

Something is growing on the wet parts: the evaporator coil, the drain pan, or the inside of the duct just after the air handler. The first blast of air when the system starts carries it into the room, then it fades as the coil cools. It gets worse in spring and fall, when the system runs in short bursts. The fix is cleaning the coil and the pan, clearing the drain and keeping them that way; a UV lamp at the coil stops it coming back.

Use the best filter your system can breathe through. Filters are rated by MERV: 8 catches dust and pollen, and 11 to 13 catches the fine particles that matter for allergies. The catch is that a denser filter also restricts airflow. A dense one-inch filter in a slot designed for a cheap one starves the coil of air and costs you cooling. A thick media filter in its own cabinet gives you the high rating without the restriction. Which one fits depends on your system, and we measure the airflow to find out.

Sometimes it is, but less often than it's sold. It's worth doing after construction or a renovation, after a pest problem, when there's visible growth inside the ducts, or when you can see dust blowing from a register. On a clean, sealed system it does little, because the filter is already doing that job. What's usually worth more is finding out why the ducts got dirty, such as a return pulling from the attic, a joint open above the ceiling, or a filter that doesn't fit its slot. We check for those causes before we recommend a cleaning.

A UV light works well at the coil. A UV lamp mounted over the evaporator coil keeps the surface from growing the film that causes the musty smell and the slow loss of airflow. It does very little for the air in your rooms, because the air passes the lamp too fast to be treated. So it's a good answer to a coil that keeps growing things, and a poor answer to dust or allergies, which are a filtration and sealing problem.

You hear back within the hour with the name of whoever is coming and when they'll arrive. Emergency calls are answered until 11 PM.

Yes, you get the quote in writing. We explain what we found and write up what it takes to fix and what it costs. Nothing is done until the person who signs off has approved it, whether that's you, an owner, a board or a landlord.

Yes, we repair, maintain and replace rooftop units. Rooftop package units are most of what sits on a commercial roof in West Orange County. We also work on the split systems inside the building and the thermostats and controls that run all of it.

Yes, planned work can be scheduled outside your hours: early, late or on a day you're closed, agreed with you first. Emergency calls are answered until 11 PM.

Yes, we offer maintenance plans for commercial buildings. A plan puts the visits on a calendar before the season instead of after a failure, and it keeps every unit's history on file. What a plan covers depends on the building and its equipment, and the plans page has the detail.

Yes, several buildings can sit under one account, with one point of contact, one invoice and every unit on file. Tell us how many buildings you have and where they are, and we work through them starting with the ones causing the most trouble.

Yes, we send a certificate of insurance on request before the first visit. Landlords and general contractors usually ask for one before roof access, so mention it when you call and it will arrive ahead of us.

We need the address of each building, how we get onto the roof, and who signs off on a quote. If you already have a list of the units and their ages, send it. If you don't, we make one on the first walk and you keep it.

We deal with both of you. The lease says who can touch the equipment and who pays for what, so we read it first. We send the landlord whatever the lease asks for before anyone goes up, and we keep you both informed. The repair keeps your store cool, and the paperwork keeps the landlord covered.

Yes, we schedule planned work around your business hours, early or after close, agreed with you first, so the door stays open.

A thermostat only reports the air around it, so it can't tell you what the unit on the roof is doing. A warm floor with a normal reading usually means the unit is short on capacity or refrigerant, a coil is dirty, or the cool air isn't reaching the floor. We go up on the roof and measure, rather than reset the thermostat and leave.

Usually because the unit is fighting the kitchen. Cooking makes heat all evening and the hood pulls the cooled air out of the building with it, so a unit that would be fine for the floor area alone is short for the real load. We measure the load with the kitchen running before we blame the unit.

Yes, we schedule planned work between services or after close, agreed with you first, so the dining room stays open.

No, we don't work on walk-in coolers or reach-in refrigeration. We handle the heating, cooling and air for the building: the rooftop units, the split systems, the controls and the make-up air. Walk-ins and reach-ins are a job for a refrigeration contractor, and we'll tell you that on the phone rather than guess at them on your roof.

Usually not, because one warm room on a system that cools everywhere else is normally a balance problem. The cause tends to be a damper, a run of duct, or a return that was never finished in the build-out. We look at the room before we look at the unit.

Yes, filtration is part of the work in a clinic. We fit better filters in the returns that serve the waiting room and the exam rooms, put them on a change schedule so they aren't forgotten, and balance the air so each room gets its share.

Yes, we schedule planned work in a clinic around your hours: early, late or on a day you're closed, agreed with you first.

You hear back within the hour with a time window and the name of the tech who's coming. How soon the van reaches you depends on the day and on what's already booked, but a house with no cooling in July doesn't wait for next week. Emergency calls are answered until 11 PM.

Call us, because a person answers emergency calls until 11 PM. After that, leave a message and you'll be our first call back in the morning. While you wait, if there's ice on the unit, switch the system to off and the fan to on so the coil can thaw before the tech arrives.

We cover Winter Garden, Ocoee, Oakland, Windermere, Horizon West, Clermont, Minneola and Apopka and the towns between them, from our office in Winter Garden. If you're further out, call us anyway, and we'll either say yes or give you the name of someone closer.

For a house, yes: someone over eighteen who can let the tech in and say yes to the work. For a business, a contact who can approve the quote by phone is enough. Tell us who that is and where the access is when you request service, and the tech won't be standing at a locked door.

It depends on what we find, so the honest answer is the one you get on site: the tech diagnoses, tells you what it is and what it costs to fix, in writing, and nothing is replaced until you've said yes to that number. We don't quote a problem nobody has looked at.

The tech stops and tells you before doing anything beyond the quote. You can approve the new price or decline it, and nobody carries on assuming you'd have said yes.

When the work's done, the invoice comes to your phone and you pay it there, card or bank. A card in person works too. Commercial accounts can have the invoice sent to whoever pays the bills.