Heat Pumps, AC and Furnaces

Duct mastic is a fast way to seal gaps in duct work. Put it on nickel thick. I put a rubber glove on, then a cotton glove on top, then smear it on. Cheap paint brushes work fine too. RCD brand is known as the gold standard. Buy an extra, go heavy. Don’t let this stuff freeze. Big boxes carry it near the duct work.

Foil tape for duct work. Best used for bath fan ducts. DO NOT use duct tape, it fails, this lasts much longer. Duct mastic is a far better solution. Available at big boxes for $8-12/roll. Look for 3M or Venture Tape, I’ve had bad luck with off brands.

DO NOT BUY THIS. This is an example. A 3 ton (36,000 BTU) heat pump with two stages. No furnace. This can replace a furnace if the work is done right, and the house will be all electric. Many homes under 2000 square feet can be heated with this. We prefer higher end equipment than this with more stages.

DO NOT BUY THIS. A small 40,000 BTU two stage furnace with a single stage 2 ton (24,000 BTU) air conditioner on top. For a few hundred more, the AC can be a heat pump which can give you good load matching. (See the HVAC Sizing chapter for more.) This is the smallest furnace normally available. 

DO NOT BUY THIS. Goodman is the only brand that sells to the public. This is a pretty standard high efficiency furnace. 80,000 BTUs is a very common size. Note that for furnace only it’s pretty cheap at $800. Typically they are way too big for client homes and hence don’t run for long, leading to poor comfort. See the HVAC and HVAC Sizing chapters for more.

DO NOT BUY THIS. This is a low end 2 ton mini split heat pump. 16 SEER is mediocre for these, the best ones are in the 30 range. 

Paladin PA70076 Tools DataShark Cable Tie Gun. Use this to tighten zip ties on flex duct joints to keep them from leaking. Hand tightening zip ties doesn’t do a good enough job. 

DO NOT BUY THIS. This is a ducted mini split heat pump which can be put above or below a few rooms to heat and cool them. It’s not very high efficiency at 16.5 SEER.