Supply Ducts

October 10, 2021

Over the last couple of weeks, I installed the supply ducts that take air from the air handler, ERV and dehumidifier, and distribute it around to different vents through the ceiling.

These ports were each built using two inline-duct connectors joined together.

I first cut holes and then foamed in three main lines for the air handler and the dehumidifier.

Getting two 10 in. and one 14 in. duct in this tight space required staggering them a bit.

Later I will use the other side of these ports to connect up the equipment.

The ERV line is a 5 in. duct, tucked behind the ERV, which will be harder to install but at least out of the way.

I made one for the ERV as well, which supplies fresh air.

I used special nylon webbing to hold the duct up into the cavity.

I had to modify one of the rafter blocks to get the duct through, but otherwise the ERV line ran nicely in the rafter bay.

These corner supports ensure the duct doesn’t kink when it’s tugged during installation or when it settles later on.

I made a wide sweeping corner to improve airflow.

The duct boots are oversized to reduce noise and have gaskets to reduce leaking.

I also put all ten of the duct boots in place, in most cases having to remove some of the closed-cell foam from the ceiling to get them to fit.

These metal parts ended up adding up to a much lager expense than I expected.

The entire system uses a number of wyes, reducers and elbows, all of which are done with rigid connectors.

The ducting is a special type of flex-duct that has a special sound-deadening inner lining.

The smaller air-handler line runs to just above where desk will be.

Multi-way wyes like this are often made from a square box, but this design should improve airflow.

The larger air-handler line splits up into four smaller lines in the live room ceiling.

It started to get very crowded up there, but ultimately careful planning paid off.

The ERV and dehumidifier lines also runs to the live room ceiling, where each splits in two.

It’s a shame you won’t be able to see this after the drywall goes on.

The final result is three lines leading to ten vents, distributing hot, cold, dry and fresh air where it needs to go.