One of the biggest concerns many seniors have when installing a new stair lift is how much is it going to cost to run. It’s a reasonable concern, as many seniors are on fixed budgets and can’t necessarily afford to absorb additional costs running their house. But when it comes to getting up and down stairs, there are only so many options available if a senior cannot manage it themselves.
The cost of running a stair lift typically involves maintenance and power. The good news is that the cost of powering a stair lift is extremely low. This guide goes into a few of the figures behind this assertion.
Domestic appliances and devices such as fridges, vacuum cleaners, computers and even stair lifts have a wattage rating, and from that, it’s easy to work out how much power they consume on a daily basis. In theory.
The problem is that most stair lifts don’t have to disclose the wattage of their motors because they’re not covered by the same regulations as domestic appliances. As a result, it requires a bit of digging in repair manuals, electrical diagrams and with OEM manufacturers as well as some sneaky maintenance of a friendly neighbor’s stair lift to hunt down actual wattages.
The average stair lift draws about 250 watts. This is in line with what’s expected, simply because stair lifts don’t have to accelerate hard, and the force required to lift a 220-pound human 10 feet in the air is about 3 kilojoules. Wattage is simply a measure of the number of joules consumed per second. The motor wattage allows for significant inefficiencies, such as the weight of the stair lift itself, friction and the weirdly complicated random factors that physics throws up.
However, energy costs are measured in kilowatt-hours. A 1,000W vacuum cleaner running for an hour costs 1 kilowatt-hour. On average, a kilowatt-hour costs 13.26 cents in the United States, but it can go from a low of 9.34 cents if you’re in Louisiana to a whopping 28.87 cents if you are in Hawaii.
So, to work out the cost of operating a 250-watt motor for a minute, it’s essential to work out how many kilowatt-hours the motor uses: 0.25 each hour. Divide it by 60, and that gives the kilowatt-hours it uses in a minute: 0.00417. Times that by the cost of each kilowatt-hour (using the U.S. average), and it’s 0.055 cents per minute.
This question is even broader than the previous one: It depends on how many people are using it and the setup of the house.
At the very least, most seniors use their stair lifts twice a day: once in the morning and once in the evening. This assumes that major facilities, such as the toilet, the kitchen, the living room and other amenities are all located downstairs.
Seniors who only have a toilet upstairs may need to use it a little more often. Without being too indelicate, the average human urinates between four and 10 times a day. This means around 12 journeys in total — six up and six down. This makes the assumption that some of these happen at night.
Assuming a worst-case scenario of 20 journeys in a day, all drawing the maximum wattage, and a transit time of one minute for each journey, and it may cost 1.1 cents a day. That’s roughly $4 a year.
Many stair lifts (including the best stair lifts) have battery power through a dedicated charging point, and this allows them to carry on working even in the event of a power outage. In some cases, charging happens across the entire length of the rail (the track that the stair lift follows) and in others, charging only happens at a dedicated point on the rail.
Batteries require charging, and the typical lead-acid battery underneath the seat of a stair lift provides 7 amp-hours at 12 volts. This is good for around 15 journeys. This sort of battery discharges 0.084 kilowatt-hours.
However, charging a battery isn’t 100% efficient. Most lead-acid batteries are about 80% to 85% efficient, and they require a floating charge to ensure maximum use. This is because they’re very slow at charging, so most stair lift designs keep them topped up.
However, this doesn’t add much extra cost — the total is 1.31 cents for electricity use per 15 uses. Scaling up results in a yearly cost of about $6.38, assuming 20 uses each day, every day.
Compared to the cost of maintenance and replacing batteries every few years, the overall electricity cost is negligible. It’s not a high-power system, with vacuums, computers and other devices routinely drawing much more power, and because it tends to be used infrequently, it’s not constantly drawing power from the system. While adding a stair lift does have a significant cost, the cost of electricity is so small it’s barely worth considering.