Big houses are the minimalist/tiny-living advocate’s whipping boy for many of the world’s ills. Few things are as easy (or big) of a target as a big houses; they take up too much land leading to sprawl, they use too many resources to build and maintain and they have too much storage space for the accumulation for extraneous stuff.
But there’s nothing inherently wrong with big houses. Okay, they take more to clean, and sure the potential for accumulating more stuff than one needs increases, and yes, all things being equal they use more resources to make and maintain (though both of those things can be mitigated significantly with best practices). But, at least to a great extent, a big house can be competitive with a small one in terms of efficiency and resource use.
How can that be, you ask?
As we’ve seen with household size (the number of people living in a home or “dwelling unit”), other factors contribute greatly to housing efficiency. For example, ten 200 sq ft tiny houses with one-person living in each house will probably be a lot less efficient than one 4K sq ft multifamily home with a ten people. Even though they have half the floorspace, the tiny houses, unlike the multifamily home, would each require their own thermal envelopes, plumbing and HVAC systems and so forth. Most importantly, the tiny houses would each have their own lots, swelling the size of the land necessary to accommodate them.
In addition to house and household size, lot size is a critical figure in understanding a house’s overall efficiency.
The average lot size for a new single-family home sold in the US in 2013 was .35 acres or 15,456 sq ft. Combine this with an average household size of 2.54 people and you have the average single-family-home-dwelling American occupying over 6K sq ft of land. [NB: the Census doesn't distinguish household size between single-family and multifamily homes, so actual household size for single-family homes might be slightly higher]. If we reduced the size of our lots, even if housing size didn’t change or even increased, it could significantly reduce sprawl and improve housing efficiency.
In understanding how lot size affects sprawl, it’s important to understand a lot’s allowable floor area ration or FAR. The FAR is the ratio of gross floor area in relationship to lot size. A 4K sq ft building on a 1K sq ft lot will have a FAR of 4, or conversely a 1K sq ft building on a 4K sq ft lot will have a FAR of .25 and so forth. Typically, FAR is a big deal in cities, where developers want to squeeze every bit of use from a lot’s area.
But FAR has many suburban implications. Consider this: if the average new home in the US is 2,662 sq ft and occupies a 15,456 sq ft lot, it has a FAR of .17. In other words, it uses 17% of the lot it’s built on. But this doesn’t tell the full picture. 17% use of a lot’s area assumes a one story structure. If those 2,662 sq ft are evenly divided between two floors, a home might only take up 8.5% of its lot’s area. The rest of the lot is yard space, driveways, garages (which are sometimes not included in gross floor space), etc. When everyone gets their own mansion, plopped on a big lot, connected to other mansions by wide-laned roads and highways, interspersed with shopping centers with huge parking lots, it leads to more driving, more encroachment on nature, more sprawl.
But again, big houses aren’t the problem. If a big house has a high FAR–either a single family home occupying a small lot or a large home in a multifamily building–it can rival or beat many small homes with low FARs in terms of efficient use of land and location efficiency. Consider that a 200 sq ft tiny house on a bucolic one acre lot would have a FAR of .004, contributing more to sprawl than a McMansion. In achieving efficient housing, smaller house size might be necessary, but it’s far from sufficient.
All of this is to say that efficient housing should not be oversimplified. A big house in the right context can be a great thing. A tiny house in the wrong one can be an energy-gobbling, sprawl-creating terror. The ideal is a hybrid of modest house and lot size, where the area that is consumed is area that is used.
Large Back Yard image via Shutterstock