Precise guesstimating – or how to install a range hood

The 1st floor range hood has arrived – fresh off the press, if you will.


It is one of the more efficient Energy Star [LINK] models at a rating of 5.4 – 6.7 cfm/watt. But God knows – it may be a dinosaur in a few months, when even more efficient models hit the market. That would actually be a good thing, unless it would require again as much tenacity as it did for the purchase of this unit.

Getting the range hood installed and running would get me a lot closer to getting the kitchen completed. You may have noticed that we installed the base cabinets and counter top, but no wall cabinets to date. That is because the wall cabinets location hinges on the range hood.

Let’s take a step back. Installing a range hood with a vent out the back typically is pretty straight forward, particularly in framed buildings. Once the wall cabinets are installed, particularly the one over the stove, the range hood can be placed under the cabinet to mark the opening for the vent.

A hole is cut through the wall assembly into which one inserts the vent cap with a short duct extension. The range hood is fitted and connected to the duct extension and attached to the bottom of the cabinet – done. You can find many examples of this on YouTube or the This Old House web page.

The problem with that process is that there is not much air sealing around the vent cap and duct extension.

Because our building envelope is getting air sealed with closed cell foam on the inside of the building, I can’t wait until the kitchen and cabinets are installed. I have to install the vent cap and duct extension before the spray foam. The foam will air seal the opening around the duct.

That is tricky because how do I know where exactly the stove location is, or where the exact location of the wall cabinet will be? Let’s call this process precise guesstimating.

Because the vent duct is already installed and in place, it drives the exact location of the range hood and subsequently the exact location of the wall cabinets. I reversed the installation process for the sake of air tightness.

Fortunately, my precise guesstimating worked out pretty well … The stove is almost directly under the hood. I missed the mark by less than 1/2 inch.

I determined the location of the first wall cabinet during a test fitting of the range hood. Once the wall cabinet was up, I put plenty of silicone around the duct fitting at the back of the hood, carefully pushed it onto the wall duct, and mounted the range hood to the bottom of the cabinet.

Installing the rest of the wall cabinets was like eating cake.

Related posts:

About Marcus de la fleur

Marcus is a Registered Landscape Architect with a horticultural degree from the School of Horticulture at the Royal Botanic Gardens, Kew, and a Masters in Landscape Architecture from the University of Sheffield, UK. He developed a landscape based sustainable pilot project at 168 Elm Ave. in 2002, and has expanded his skill set to building science. Starting in 2009, Marcus applied the newly acquired expertise to the deep energy retrofit of his 100+ year old home in Chicago.

2 thoughts on “Precise guesstimating – or how to install a range hood

  1. You’d think somebody would have developed a better connection/installation for range hoods – the through wall connection seems so hokey to me “slather it with silicone and hope for the best” is pretty much what you get, eh?

  2. It is pretty much what you get. Although some attention to detail when “slather the silicone” and fitting the range hood onto the through wall duct helps a lot. In other words, take your time, and you don’t have to hope for the best that much any more…

Leave a Reply

Your email address will not be published. Required fields are marked *