IDEAL Window Installation

Improving Best Practices


You bought high-performance windows, but is the install going to complement their performance or detract from it? The enclosure insulation, airtightness and moisture control should be continuous. But too often where the window frame meets the building we see breaks in insulation, air leaks and vapor traps - all setting the stage for discomfort, inefficiency and moisture damages. The ubiquitous can of Great Stuff by Dow Chemical provides a connection that is neither airtight or healthy - with foam residue and waste chemicals left to bioaccumulate in our environment already choking on plastic.

Makes good toxic garbage.Cans makes good long-term toxic garbage.

We can improve our window install by using more natural, safe and healthy materials that are easier to install and more reliably durable for the long term. No builder likes struggling to insulate around windows with messy spray foam insulation or backer rod and caulk. These options are tough to install well, and are often vapor closed, short term, and generate a lot of waste. Stop it. There is a better way. You might say we have an IDEAL solution based on Havelock Sheep's Wool insulation and Pro Clima tapes:

We like simplicity.


Add sheep’s wool insulation around the window frame to ensure insulation continuity. And improve the performance of your windows with > R-4/in. surrounding the window frame. The sheep's wool is easy to handle, doesn't itch and is hygroscopic.


Managing moisture is crucial to long-term durability, so not only do the Pro Clima tapes manage moisture, so too does the sheep's wool. It will not rot or foster mold, and it helps buffer moisture, increasing drying safety buffer and helping ensure long-term durability.

Ease of Install

Installing wool insulation around the window frame doesn't require any protective equipment, won't make your hands itchy, and is quick and simple to install. Add Pro Clima fleece-backed tapes for a finish that is clean and doesn’t require scraping out a mess of expanded spray foam.


Installing Pro Clima's airtight tapes in an airtight manner allows us to keep the insulation airtight and performing to its optimal level. Continuous, verifiable airtightness also limits heat loss, improves comfort, and prevents unplanned moisture intrusion and damages where thermal bridges and condensing surfaces are most likely to be found.


Pro Clima's tapes and Havelock sheep's wool insulation are VOC-free, and have achieved the DECLARE label from the International Living Futures Institute. Additionally sheep wool is a non-toxic, renewable material that actively filters toxins, absorbing VOCs like formaldehyde. This is what doing better looks like.

The combination of Pro Clima and Havelock optimizes the assembly.

The Install Sequence

The installation process is quick, clean and simple. Just three easy steps:

First - Water protection at the sill. Prepare the rough opening and properly set the window in place. We recommend EXTOSEAL Encors as a watertight sill tape, along with the right Pro Clima window tape designed for the substrate and the taping style you prefer. Keeping it all within the Pro Clima family provides a 10-year System Warranty.

Acrylic Butyl adhesive tape - the EXTOSEAL Encors is the ideal sill tape.Acrylic-Butyl adhesive tape - EXTOSEAL Encors is the ideal sill tape.

Second - Insulate with Havelock Wool. From the interior side, use Havelock sheep's wool insulation (loose-fill or batts cut to 4” wide) around the window perimeter using a Pro Clima PRESSFIX applicator, a flat bar, or a carpenter’s pencil.

Loose-fill or batt, Havelock Wool is a natural, comfortable and effective installation solution.Loose-fill or batt, Havelock Wool is a natural, comfortable and effective installation solution.

Finally - Air and vapor control with Pro Clima tapes. On the interior side, use Pro Clima's TESCON Profil, TESCON Profect or vapor retarding CONTEGA Solido SL tape to connect the window frame to the inboard airtight layer - either INTELLO Plus or the plywood buck. Make pre-folded corners per our guide to ensure continuity between sill/head and jamb leg taping. On the exterior side, you can also use Pro Clima's TESCON Profil, TESCON Profect or use waterproof + vapor open CONTEGA Solido EXO tape to connect the window frame to the outboard airtight layer: one of the Solitex membranes.

For a full explanation of window installation possibilities see our post: How To Prepare For High Performance Windows.

TESCON Profil with split backing for ease of installation at tight inside corners.TESCON Profil with split backing for ease of installation at tight inside corners.


Durable, healthy and efficient, the IDEAL window package is a simple and straightforward approach to ensuring a high-performance install of your high-performance window. Choose Havelock Wool and Pro Clima Tape.

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