How to calculate the price of affordable universally accessible homes

How do we figure out what makes a universally designed home affordable to build?

How do we figure out what makes a universally accessible (i.e., universally designed) home affordable?

Let’s start with the “affordable” part. What percentage of income is okay to spend on housing? Depending on who you ask, the recommendation is around 25-30%.

We need to understand income levels and that there’s little consistency here, but we can use the “area median income” (AMI) for any given area as a starting place.

Let’s not overlook the people who will benefit from universal design the most (at least immediately): people affected by disability. This includes individuals, family, and friends. When we add disability into the equation, the average household income decreases by 37% (using national 2018 data from

For example, we live in the small-ish city of Harrisonburg, VA. Using the first source of data after searching Google for “Harrisonburg VA area median income” (, in 2017 numbers, the median household income is/was $43,009.

If we adjust $43,009 down by 37% to account for the difference in income between households with and without a disability, we end up with $27,096 per year. Divide that number by 12 and a household with a disability in our area, on average, has $2258 per month to cover all of their expenses.

I mention the word “expenses” because it’s often overlooked that life with a disability includes expenses that others don’t often have. This may include DME (“durable” medical equipment), medical supplies, extra health-related items (therapy, prescriptions, caregivers, and the list goes on), not to mention higher insurance costs. In other words, life with a disability is more expensive than life without disability.

So when we look at what makes housing affordable, we’re going to say that 25% of one’s income is a good ceiling for what should be spent on it. Any more starts to affect life in other negative ways.

Back to our example of Harrisonburg, VA, that means that spending more than $565 per month on housing can put the average household with a disability in our area in a financial bind.

You can calculate this number for your area too. Chances are good that the number is WAY under the average amount that people spend on housing. This is a big problem.

Based on the calculation above, we know how much is an affordable and reasonable average amount for a household to spend on housing. But how does that translate into what we need to design for?

If we take the average monthly amount that the average household with a disability should comfortably spend on housing and plug it into a mortgage calculator (e.g., Google’s), we can get an idea of how much someone could borrow and spend on a home.

With zero downpayment and an interest rate of 3.92% over 30 years, a $565 monthly payment would allow someone to borrow $119,497. That’s it. Again, this number is probably WAY under the average home price in your area.

We’re not done yet, because the sale price of a home includes a lot more than the cost of construction. In fact, construction costs were only 61.1% of the average sale price, using 2019 data from the National Association of Home Builders.

So now we’re getting somewhere. If we want to design an affordable home, we have to look at the construction cost as the target. In the Harrisonburg area, that means 61.1% of $119,497, which is $73,013.

Affordability is a big challenge. Can it be done with design alone? Maybe. We’re optimists and think it can, though we’re also realistic and understand that land costs and other items like zoning restrictions are out of our control, not to mention pushback from other homeowners if more affordable options are built nearby.

Here’s the thing. Architects are smart and understand different materials and construction methods. But then we add that extra variable of universal accessibility into the equation. It’s not realistic to expect that an architect or other design professional will understand what makes a home functional for any possible individual with any possible impairment or health condition, so we have to involve health professionals, and ideally, people with lived experience with disability. This drives the cost of design up and up… and up.

This is also why it doesn’t make sense to treat universal design as “custom.” Sure, if a client has a big budget and can spend more on design, that’s great, but it doesn’t address the widespread problem of the lack of affordable universally accessible housing. That’s much more complicated, especially if the “affordable” part means that housing has to cost less to build.

If you ran the calculations above for your area, whether you’re in the USA or not, I’d love to hear what you came up with. Could you only spend 25% of your income on housing and still have a decent place to live? Leave a comment below and let me know.

In summary:

  1. Find your area median income.
  2. Multiply by .63 to adjust down 37% for households with disabilities.
  3. Divide by 12 to find the monthly income.
  4. Multiply by .25 to find the max amount to spend on housing per month.
  5. Plug that number into a mortgage calculator to figure out how much home is affordable.
  6. Multiply by .61 to determine the target construction cost.

Again, there will be a lot of variability in individual situations, location, and more, but if we want to look at the goal for designing for accessibility and affordability, this is a good place to start.

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