How much can I expect to save with insulation improvements?

How much can I save?

How much you can save depends on the access you have to your insulating
surfaces, look at the chart below and pick the statement that comes the
closest to matching your situation.

Your Situation

Potential for Savings (% of fuel bill)

Early stages of planning for new construction1

40-70%, 100% if you are planning a zero energy home.  The planning phase of construction is THE best time to get a whopping return on insulation upgrades. 

House is in construction but no insulation yet2

30-60%, last minute changes in insulation may not go over well with your contractor but he/she will get over it if you are willing to work with them on cost

Existing house with plans for gutting and major renovation2


Existing house with plans for minor renovation

5-40% depending on the renovation. If the area you renovate happens to also be a weak part of the envelope you may get a big return.

Existing house with no plans for renovation but the basement and attic are unfinished

Up to 30%, 40% possible but not common.  You can get a good return from air sealing an attic or stone foundation.  Also uninsulated foundations can yield a good return with the first R5 that you add.   

You have an old house with little or no insulation in the walls, attic, or basement

40-60% Congratulations! There are many places to get a fast return on your insulation investment.

Existing house with no plans for renovation and the basement, attic, and cathedral ceilings are finished

See “weatherizing a house” below. 

Considering new siding

5-40% If the walls have no insulation there’s a large opportunity for savings by adding insulation.  Adding a layer of rigid foam before new siding can help but it’s impact will be less if your walls already have some insulation in them.

Considering a new roof

5-40%, Here’s an opportunity to add insulation to the roof or make the existing insulation airtight.  If the roof was a weak spot previously the potential for savings is high. Having an airtight “lid” on the home provides benefits for the whole home.   

Considering window replacement

5-20%, over 20% is possible but not common.  Good quality storm windows can improve your window air-tightness and R-value at a reasonable cost.  If greater than 30% of your wall area is glass consider reducing the size of some of your windows when replacing them.  

Weatherizing the house: i.e. adding weather stripping to the doors, windows, and attic hatches, adding more attic insulation, replacing door thresholds, sealing visible holes with caulk, foam inserts for the electrical outlets, etc.

5-20%, over 20% is possible but not common.  If you are really serious about weatherizing have an infrared scan done to identify unseen locations of air leakage, your opportunities to save will increase.  

1.Important note: At the early planning stage innovators are able to build homes and buildings that are 50-70% more efficient than average at the SAME COST as conventional construction.  How?  They carefully down size, or "right size", the heating system to fit the high efficiency insulation system.  The increased cost of the shell is offset by the decreased cost of the heating system and the house costs the same.  I've personally participated in such projects so I know it works.  Here are some links to a couple of projects that you should know about Coldham Hartman, FOAM-TECH).  This approach is still considered risky by many, especially heating and cooling system professionals but many industry insiders, myself included, think it is where we need to be going.  So, consider it if you are the “early adopter” type. You need to hire a consultant to design a high efficiency building envelope and then calculate the heat load of your building so that you can size your heating system to that load. 

2. Energy Star™ homes target a minimum of 15% savings over a minimally code compliant home.  This target combines savings from lighting, appliances, spacing heating/cooling AND the building envelope.  Insulation-Guide believes that in the stage of new construction and full house renovation (gutting the interior) you can shoot for a higher percent savings.  Like Energy Star™, you don’t get these savings without investing in energy efficient methods and materials. 

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Below is a site that can help you to plan for maximum savings based on the situation you are in. Take a look.