Webasto Diesel Heating and A/C

[Lee Hadjiosif]

I have a 42' sailboat with Webasto diesel heating and 3" ducting throughout. I now want to install A/C as well. Should I try to install one large unit and utilize the existing ducting with a Y valve or run parallel ducting for A/C? The heating duct is smaller and not insulated but I can always wrap it with insulation. My concern is with the ability of the heavier cooler air to utilize the existing 3" duct. I hate to cut large holes again in the bulkheads and walls and the cost of the A/C installation will be reduced considerably. Has anyone done that effectively? Thanks.
CaptainLee

 

[SG]

NO. First, your ducts really aren't sized for AC. Secondy, the location if the diffusers are probably at the floor and not higher up. We retrofited an AC unit on our Sabre 42 over 25 years ago and didn't use our Espar heaterducts for those reasons. When we had our J/160 outfitted, we used separate supply duct systems for AC and heater. You should be able to find a location for AC in you Beneateau.

I'd call Nate Horton at Horton Marine -- I've found him to be the best refrigeration and AC guy in Annapolis. (BTW, he's Cleave Horton's son, the founder and owner of Seafrost.)

 

[Lee Hadjiosif]

SG, Thank you for your feedback. Everything you said makes sense and is true. However, I know that there are some that used the existing heater ducting for A/C and want to know how much of a "trade off" there is. If it's a matter of increasing the unit size a little to compensate for losses, it may be worth it to avoid new ducting. It's going into a Jeanneau 42 DS with only two cabins.

 

[MitchM]

pull the install guide from marine air and cruise air. undersizing your ac exhaust ducts will void the warranty and give very bad ac performance. no reputable AC installer would touch this.