Boulder City Air Balancing
Most of the Boulder City homes we balance were built in an older era and changed afterward: a den closed in, a family room pushed out the back, a bedroom added on. The ducts stayed the size they were. That is why one room runs warm all summer and chilly on winter nights while the thermostat reads fine. We put an Alnor flow hood on every register, write down what each room really gets, and adjust from those numbers.
Add-On Rooms the Original Duct Run Was Never Sized For
A ranch house built here between the 1950s and the 1980s got a duct system designed around the floor plan it had the day it was finished. The trunk, the branches and the blower were matched to those rooms. Then the house changed. A patio became a family room, a back bedroom went on, a garage corner got walled off for an office. The ducts almost never grew along with it.
Usually the new room gets a branch tapped off whatever run was closest, often near the end of the line where pressure is already lowest. The blower is the same blower, so every bit of air that reaches the add-on comes out of the rooms sharing that trunk. The add-on is the last room to cool in summer and the first to go cold in winter, and sometimes the room it borrowed from slips a little too.
The common homeowner fix is to shut vents in the rooms that feel fine. That raises the pressure the blower works against and trims total airflow, so the add-on gains a little while the system as a whole loses more. Before we move a single damper, we measure what the added room actually receives and compare it to what its size and its exposure call for.
Dam-Era Cottages Breathing Through a Single Return
The federal government built Boulder City in 1931 for the people building Hoover Dam, and the cottages and bungalows in the historic downtown come from that period. They were not designed around ducted air. Whatever system serves one now went in later, and the layout we find most often is a handful of supply registers feeding back to one return grille, usually in a hallway.
One return works fine with every door open. Close a bedroom door at night and the air pushed into that room has no easy way back. The room pressurizes, its supply drops, and it drifts off temperature while the hallway thermostat stays satisfied. We read each bedroom supply with the door open and again with it shut. A big gap between those two numbers points at the return path, and the equipment itself is usually fine.
The fix tends to be small: an undercut door, a transfer grille, a jumper duct between the room and the hall, or a second return where the framing allows one. A lone return also pulls hard through its filter, so static pressure at that grille gets checked on the same visit.
Register by Register, Then a Report You Keep
Balancing starts with the system running at normal conditions. One of our NCI-certified techs sets the flow hood over each supply register and records the airflow room by room. Returns get read too, along with static pressure across the system and the temperature split at the coil. Each room then gets a target based on its size and what it faces, and the readings show which rooms run over and which run short.
Adjusting takes a few rounds. Close a branch damper partway to slow a room that gets too much, and every other room on that trunk shifts with it. So we adjust, read again, and adjust again until the numbers sit close to target across the house. Our air balancing work on commercial buildings around the valley follows the same method.
When we finish, you keep a written report: every room’s airflow before and after, the target for each, static pressure, the temperature split, and notes on anything the dampers could not correct. Whoever works on the system next, including a different company, starts from real numbers.
One room that never matches the thermostat?
Describe the house and the room, and we will bring the flow hood. You can also send the details in writing and we will call you back.
Two Floors, Split Levels, and Air That Rises
Two-story and split-level homes add a problem a single-story ranch does not have. Warm air rises. In summer the upper level collects heat from the rooms below and from the roof above, and in winter the lower level stays cool while the warm air drifts upstairs. Most of these houses run one system on one thermostat, which sits on one floor and only knows what that floor feels like.
Boulder City sits around 2,500 feet, above the valley floor, so the town gets long hot summers and real heating nights in winter. A two-level house here can be off in both seasons, in opposite directions. The upstairs bedrooms that bake in August are the same ones that run stuffy in January while the family room downstairs stays cold.
The practical answer is two damper settings. We find a summer position that sends more air upstairs and a winter position that favors the lower level, mark both on the dampers, and record them in the report. Switching takes a few minutes twice a year, and we walk you through it before we leave.
Where Damper Work Ends and Duct Work Begins
Balancing redistributes the air the blower already moves. If the total is healthy and the split between rooms is off, damper adjustments solve it, and that is how it goes in a good share of the homes we measure. What dampers cannot do is push more air through a branch that is too small, too long, crushed in the attic, or pulled loose from its boot.
The readings tell the two apart. A room that stays short with its own damper wide open and the others trimmed back has a duct problem. So does a system whose total airflow comes in low before we touch anything, which often means leakage. Then we recommend duct leakage testing first, because balancing a leaking system means some of the air you balanced never arrives.
Duct fixes range from resizing one branch to adding a run or a return. For an add-on the trunk simply cannot feed, a ductless mini split is sometimes the cleaner answer.
What Boulder City Homeowners Ask Before a Balance
Will closing vents in other rooms push more air to my add-on room?
Not much, and it can make things worse. Closing registers raises the pressure the blower works against, which cuts total airflow and can starve the coil. A small amount reaches the add-on, but adjusting branch dampers moves air far more predictably than a handful of shut vents ever will.
My cottage has one return in the hallway. Is that a problem?
It can be. With one return, every closed bedroom door blocks the path air takes back to the system, so supply to that room drops. We measure with doors open and shut. If the difference is large, a door undercut, a transfer grille or an added return usually fixes it.
What do I get at the end of a balancing visit?
A written balance report. It lists the airflow at every supply register before and after our adjustments, the target for each room, static pressure across the system and the temperature split at the coil, along with notes on anything that dampers alone could not correct.
Why is my upstairs hot in summer and my downstairs cold in winter?
Warm air rises, and most two-story and split-level homes run one thermostat on one floor. A single damper setting cannot suit both seasons. We find a setting for summer and another for winter, mark them, and show you how to switch between them when the weather turns.
Can balancing fix a room that was added on decades after the house was built?
Sometimes. If the branch serving it is sized well enough, adjusting dampers elsewhere sends it more air. If the branch is too small, too long or kinked, no adjustment delivers what the room needs, and the readings will show that a duct change or a mini split is the better answer.
Is air balancing worth doing before I replace my AC?
Usually, yes. A new unit on a distribution problem cools the same rooms well and the same rooms poorly. Balancing, paired with a duct leakage test, shows whether the equipment is really at fault. Plenty of the homes we measure end up needing their air redistributed and keep the equipment they have.
More Boulder City Work From the Same Crew
Balancing is often the first visit and rarely the last one. The four pages below cover the other jobs we handle in town.
All Boulder City HVAC services · Photos of past jobs · Book a visit
Boulder City and the Ground Around It
The town sits at around 2,500 feet on the edge of Lake Mead National Recreation Area, with Hoover Dam a few miles to the east. We cover it as part of our regular service area, and the map below marks the town for reference.