New Construction HVAC for Homes and Additions in Oakland County

Designing a new home's HVAC properly from the start

Good design follows three steps, in order. First comes a room-by-room load calculation, known in the trade as Manual J, which works out how much heating and cooling each room needs from its size, insulation, windows and the direction it faces. Then equipment selection, Manual S, which matches a furnace, air conditioner or heat pump to that load. Then duct design, Manual D, which sizes every supply and return to carry the right amount of air. That is accepted best practice.

New homes are generally better insulated and tighter than old ones, so they tend to need less heating and cooling than habit suggests, and equipment that is too big is the common mistake. An oversized air conditioner cools fast and shuts off before it has pulled the humidity out. In this part of Michigan, winter asks far more of the system than summer does, so the heating side deserves the closest look.

The ducts are the other half. According to ENERGY STAR, a typical duct system loses 20 to 30 percent of the air moving through it to leaks, holes and poor connections. New construction is the one time every joint is within reach, so that is when to seal them with mastic or metal foil tape, and to keep the ducts inside the heated part of the house wherever the plans allow.

Furnace and AC, heat pump or dual-fuel for a new build?

Where natural gas is at the street, a gas furnace with central air conditioning is the familiar choice and still a sound one. A cold-climate heat pump is a real alternative now: models that carry ENERGY STAR's cold-climate designation have to meet heating output and efficiency requirements at 5 degrees Fahrenheit. Dual-fuel pairs a heat pump with a gas furnace, so the heat pump handles mild weather and the furnace takes over in the deep cold.

A tight new house also needs planned fresh air. That usually means an HRV or an ERV. Which one fits depends on the house, and our ventilation page explains the difference. A large or two-story plan may also be better served by zoning or by two smaller systems than by one big one.

Can the existing system carry an addition or a finished basement?

Sometimes. The honest answer comes from numbers, not from a glance at the furnace. We work out the load of the new space, compare it with the spare capacity of the equipment you have, and then check the part people forget: whether the existing ducts and blower can move the extra air. A furnace can have heat to spare and still be feeding a trunk line that is already at its limit.

Finished basements are often the easy case. The load is small and the main trunk is usually right overhead, so adding supplies and a proper return, set low where the layout allows, is often enough. Dampness is the thing to watch, and a dehumidifier may do more for the space than extra cooling would.

Additions, bonus rooms and garage conversions are different. They tend to be far from the furnace and have a lot of outside wall. When extending the ducts would short the rest of the house, a ductless mini-split is often the smarter answer: the new room gets its own heating, cooling and thermostat, and the existing system is left to do the job it was sized for. Where both routes are workable, we price both and tell you which we would choose.

HVAC rough-in, finish and working alongside your builder

The work comes in stages. Design happens on the plans. Rough-in happens after framing and before insulation and drywall. Finish comes after paint and flooring: the equipment is set and connected, and the registers, grilles and thermostat go on. Last is start-up, when we run the system, check airflow and temperatures room by room and balance it.

For builders and general contractors, what counts is that the HVAC crew shows up on the day it said it would, because insulation and drywall cannot start until we are finished. Bring us in while the plans can still change, and we can agree on chases, return paths and equipment space with your framer, plumber and electrician before everyone is competing for the same joist bay.

Homeowners acting as their own contractor get the same treatment. We are family-owned, seven years in business, and you get the scope and the price before anything starts. You do not need finished drawings for a first conversation: a sketch and the room sizes are enough to begin. Call 248-930-2080 with your plans, or see how we handle HVAC installation in an existing home.