Do I need new ducts when I replace my air conditioner?

Not always, but the duct system has to be evaluated against the new equipment. Newer systems often move air differently than what you had, and a duct system that was already marginal can become the limiting factor. We measure rather than assume either way.

Why do a load calculation instead of going by square footage?

Because square footage does not know which way your windows face. A room by room calculation tells us how much air each room needs, and in our climate it separates the cooling load from the moisture load. Rules of thumb are how houses end up oversized and clammy.

Sheet metal or flex duct?

Both, used where each belongs. Sealed sheet metal for the trunk and fittings, where air moves fastest and pressure losses get decided. Flex for the final run to the boot, kept short, pulled tight, and supported so it cannot sag. Flex as the main system is where performance quietly goes.

Can you keep my existing ductwork?

Sometimes. If the trunk is adequately sized, the layout matches how the rooms are used, and the material is in good condition, we would rather repair and reseal than replace. We will show you the measurements behind whichever answer we give.

Why does the return matter so much?

A blower can only push what it can pull. An undersized return raises static pressure across the whole system, reduces airflow to every room, adds noise, and makes the coil run colder than it should. It is the most commonly undersized part of the systems we inspect.

Ductwork Installation & Design in Houston, TX

Ductwork Installation and Design in Houston

A new duct system is a design job. The layout decides how the house will feel for the next twenty years, and copying the old layout is often the reason the house was uncomfortable in the first place. We design it, fabricate what needs fabricating, then measure what we built.

Design comes before metal

We start with a room by room load calculation. Square footage rules of thumb do not account for orientation, window area and type, shading, ceiling height, insulation levels, or how many people use a room. Two rooms of the same size on opposite sides of a Houston house have very different loads at four in the afternoon.

The static pressure budget

Every duct system has a pressure budget set by the blower. Every fitting, turn, length of flex, register, grille, filter, and coil spends part of it. Design is spending that budget deliberately instead of discovering later that it ran out.

Fabrication

Billy Wagner came up through commercial work and spent time on a government contract overseas doing air conditioning, plumbing, electrical, and custom fabrication. That background shows up here. When a plenum, transition, or drop box needs to be made to fit a specific space, we make it rather than forcing a stock part where it does not belong.

Sealed sheet metal trunks with properly built takeoffs, mastic at every joint, and flex used only for the last run to the boot: that is the arrangement that holds its performance. Air Star Now is licensed in Texas under TACLA36229C.

Where the equipment sits, and how it drains

In most Houston homes the air handler is in the attic. That dictates a platform holding the unit level and accessible, a secondary drain pan, a properly trapped primary condensate drain, a secondary drain line, and a float switch that shuts the system down before water reaches your ceiling.

A stopped or dried out condensate trap is one of the most common and most preventable service calls we run. Building the drain correctly on day one prevents it. Service clearance matters too: if a technician cannot reach the coil or blower in five years, your maintenance suffers for the life of the system.

Commissioning

Once the system runs we measure it: total external static pressure, airflow at each register against the design number, temperature split across the coil, refrigerant charge, and indoor humidity after it has pulled the house down.

What a proper duct design includes

Room by room loadAirflow derived from each room's actual heat gain, not from floor area.
Equipment selectionCapacity matched to the load, including the moisture load our climate adds.
Trunk and branch sizingDuct sizes chosen against a friction rate the blower can support.
Return capacityA return path sized so the blower is not starved with doors closed.
Condensate designTrapped primary drain, secondary pan and line, and a float switch.
Service accessClearance to reach the coil, blower, filter, and drain later.

Ductwork Design, answered plainly

Not always, but the duct system has to be evaluated against the new equipment. Newer systems often move air differently than what you had, and a duct system that was already marginal can become the limiting factor. We measure rather than assume either way.
Because square footage does not know which way your windows face. A room by room calculation tells us how much air each room needs, and in our climate it separates the cooling load from the moisture load. Rules of thumb are how houses end up oversized and clammy.
Both, used where each belongs. Sealed sheet metal for the trunk and fittings, where air moves fastest and pressure losses get decided. Flex for the final run to the boot, kept short, pulled tight, and supported so it cannot sag. Flex as the main system is where performance quietly goes.
Sometimes. If the trunk is adequately sized, the layout matches how the rooms are used, and the material is in good condition, we would rather repair and reseal than replace. We will show you the measurements behind whichever answer we give.
A blower can only push what it can pull. An undersized return raises static pressure across the whole system, reduces airflow to every room, adds noise, and makes the coil run colder than it should. It is the most commonly undersized part of the systems we inspect.