North Sound Valuation

What is ANSI and why is it so important to home appraisals?

What is ANSI and why is it so important to home appraisals?

Why accurate measurements are important


Aside from the site related factors of view, acreage and waterfront, one of if not the biggest factor is the size of the improvements. Finished living area, which includes GLA or gross living area is frequently noted or promoted in listings, appraisals, and in conversations around the watercooler. 

The size of the home, and the buyer’s perception of that number, is one of the most frequent reasons a Realtor or an appraiser gets a complaint, or even a lawsuit. Agents often rely on county records in advertising the size of a home, but did you know that most homes have never been measured by the assessor? It is common for the assessor to rely on the submitted plans for the size of the home, and uncommon for them to measure the homes after an addition or other change in size.

Having an accurate, up to date measurement of the home is crucial to ensuring it gets full value from the market on a sale, and crucial for keeping the agents and appraisers from getting a complaint related to the size of the home.  

How most appraisers measure today/ANSI

One of the challenges for achieving an accurate measurement has been that there was no universal measurement standard. Some measured with a laser, some a tape measure, some a wheel rolled next to the home. Do we measure from the inside or the outside? Do we count a sloping roofed room all the way from the peak to where the wall meets the ceiling? Ask ten appraisers and before ANSI you’d get twelve answers.

The American National Standards Institute (ANSI) developed a measurement system that provides a predictable, consistent measuring result when applied properly. Fannie Mae has adopted this standard for use by appraisers in transactions sold to them, which largely means that all appraisers use this system in all homes they measure.    

Who is ANSI?

The American National Standards Institute (ANSI) is a private, non-profit organization that administers and coordinates the U.S. voluntary standards and conformity assessment system. Founded in 1918, the Institute works in close collaboration with stakeholders from industry and government to identify and develop standards- and conformance-based solutions to national and global priorities.

Together, standards and technical regulations impact up to 93% of global trade. Globally relevant standards and the conformance measures that assure their effective use help to increase efficiency, open markets, boost consumer confidence, and reduce costs. And ANSI is the U.S. leader in fostering that potential for the benefit of businesses across every industry and consumers around the world.

The benefits and hurdles around ANSI

The #1 benefit is that homes measured using the standard and then those measurements being used in sales and appraisals is a consistency in output, and a reliable way to check for accuracy. If someone “feels” their home was misrepresented then it’s simple to measure the home, using the standard and get a very similar result.

Before ANSI you could get wildly different results, from the various methods employed and no “correct” standard. If we’re all measuring the same way then we should get results that are well within a 5% range of difference, hopefully even closer.

One of the biggest hurdles to the use of ANSI, aside from appraiser’s intransigence, is that the assessor have yet to universally adopt the standard and architects and designers still use their own byzantine methods. Bringing all players into the fold will lead to reliable, consistent square footage results and take much of the opaqueness out of Real Estate transactions.

The ANSI measurement standard for single family homes and condominiums

The standard is blessedly brief, a few pages at most and instructs a user on how to measure above and below grade area, what part of a Cape Cod style or dormers “count” and what does not. How to differentiate between finished areas and unfinished,  What a basement is and how to report the finished area above and below grade.

Are there exceptions?

Some areas that historically have been included, are not in the ANSI standard, and can “count” and be adjusted for on their own line. If a market routinely counts areas under a sloped ceiling in a finished room then they can be accounted for within the standard, just not on the same lines as the GLA. There are other exceptions that a qualified appraiser will employ, when appropriate.


It is important that agents and homeowner’s not misrepresent a home for sale and also important that a home be measured correctly for a mortgage related transaction.

We stand ready to help, and offer home measurement services as a stand alone service, in addition to our use of the ANSI standard in all appraisal assignments.