Hot reads in a cool shop: cutting cooling costs

This is part of an air conditioner. Really.

Any bookshop owner with a small shop knows how quickly a comfortable shop can suddenly get swelteringly hot on a busy summer day.  Just add extra people! Once the temperature starts to climb, cooling costs can take a big bite out of your budget. They’re a cost that you’ll have to pay even if sales stink, so shaving money off that cost can really make a big difference in down times.

If your cooling system really isn’t up for the job, it may be time for an upgrade.  Of course if you’re in a  rental space, this may not be an option.   You’re probably stuck with the system you’ve got which was adequate for the space as originally designed and with the original number of people estimated.  Even a system that’s the right size for everyday use may struggle on a really busy or really hot day. (and keep in mind a too large system can make it really humid in your shop, not a good thing for a book store!)

People are the biggest source of heat in a building.  Air conditioning is generally measured in BTUs.    An average room will need an air conditioner that can generate 4000-6000 BTUs for a single person. (roughly, individual conditions can complicate the issue) Beyond that, start adding between 350-600 BTUs  required per person depending on how much walking around they’re doing.  (a staffer busily shelving throws off more heat than a customer sitting and reading)  A sunny window requires around 1500 per window.  No insulation? You may need up another 4000!

With numbers like that it quickly becomes obvious why your store is going from comfortable to swelteringly hot when two extra people walk in.  What’s fine for average may not work on the hottest day of the year.  And if customers are hot, they’ll leave.

Thus dealing with the air conditioning addresses two issues:  saving money and saving sales.

People are the heat source you can’t get rid of… and don’t want to! So down on running the system, you’ll need to tackle heat from other sources. We don’t usually think of equipment putting a drain on the cooling bill, but anyone that’s ever put a laptop in their lap knows just how hot equipment can get!

Exactly how much heat a machine throws various widely by item but its safe to say if it uses electricity of any sort, it generates at least SOME heat.  So don’t start the day at a deficit: if it’s not VITAL to have on, turn if off overnight.  Even better, unplug it or kill it with a power bar so it stops pulling power when off to run displays or to be kept in ready mode.  Not only does this save you electricity by powering down the item, its not generating ANY heat that way.  Even machines that are supposedly “off” draw a little power in many cases.   Not a lot, but its still making your air conditioning work just a hair harder.  Add together lots of little things like a printer left on standby, the microwave in the breakroom, the light someone forgot to shut off, the barcode scanner, it all contributes a little bit and robs you of cash.  Each may only be a few cents a day, but over time is can mount up to quite a bit of cash.  And if it contributes to it being sweltering in the store at 3PM so customers don’t browse as long, its hard to tell how much cash you’re losing indirectly.

So power down equipment overnight.  Equipment that’s not used frequently and doesn’t need a really long warming period may also be better left off or even unplugged during the day.  BTU outputs aren’t standardly displayed on most equipment, but you can sometimes find the documentation on the manufacturer’s website.  According to the spec sheet on their website, an HP laserprinter generates 375 BTUs while in standby.  It’s like having another person in the room.  (and 1297 when running!  Imagine 3 warm people sitting next to you on a hot day…) Powering it all the way down may make a big difference in the temperature in the store at the hottest part of the day.

Now, some equipment CAN’T be turned off overnight.  If you’ve got a coffee shop attached, they can’t power down the refrigerator overnight, it’s not safe.  Use common sense with what can and cannot be turned off.

And turning stuff off is free or cheap!  It may add a minute to your opening or closing routine… or none at all depending on how you set things up.  If you buy an automatic timer ($5-$30) that kills all power to a given outlet at X time, you may be able to do it all automatically and not have to worry about whether staff remember to turn things off.

The other big source of heat is sunlight itself.  Natural light is great, you want as much as you can get.  But again, there’s no reason to start the day at a deficit.   A set of roll down shades may be a great investment, especially if they can be partially lowered.  Pull them all the way down overnight.  Don’t let the sun heat the place up while you’re closed. (it can also make a nicer backdrop for things in your window this way, by removing visual clutter) If you can adjust them during the day so that light gets in without broiling the people browsing near the window, that would be ideal.    This may also help boost sales in sunny spots in the store that otherwise become too hot during parts of the day.  A little shade may make a spot people shunned for a few hours each day a good sales area again.

(If you’re in an area where police need to be able to see into the store at night, shades may not be an option.  Putting a tree in a planter outside your window may work though!  Get creative!)

Shade for your air conditioner itself may also help.  An air conditioner that’s in direct sun surrounded by a sea of heat absorbing black asphalt is going to have to work a lot harder than one in the shade!  Make sure not to obstruct air flow.  (and be sure to dust the air conditioner while you’re checking it out…)  But a shade tree, fence, or for a wall unit, a shelf ABOVE it to shade it, may make it work a lot more efficiently.

These are all relatively cheap and immediate fixes for a cost you probably only have to deal with for a few months a year.  However, if you’re somewhere you need to air condition at least half the year (or more), own the building, and plan to for awhile, you may want to dig even furthur into trying to cut your air conditioning costs.  It’s a big cost that you’ll incur even when sales are bad and its not going away.  And bad air conditioning can make your sales even worse! Energy costs are pretty well guaranteed to continue going up.   Costs are currently lower than usual for remodeling and there’s lots of state and local grants or tax incentives to try some of these out.  (your local power company may even cut you some deals too!)  Some other options to investigate are landscaping to provide shade, adding insulation, repainting the roof white, installing a cool or green roof, or totally switching cooling systems entirely to something like a greywater or ice system.

Not all these options will be economical or practical for every brick and mortar outfit, but hopefully it gets you thinking about ways to deal with vexing energy costs.  This is probably the least glamorous parts of owning your own business, but run away energy costs can run you out of business all together.

(the picture at the top of the post is of part of the air conditioning system for the David E. Lawrence convention center in Pittsburgh, PA.  It cools the water for the system by sending it down a waterfall system that looks like a big fancy fountain.  It’s the largest Gold LEED certified convention center in the US.  The air conditioning system for your store will probably never look quite this awesome unless your store is over 200,000 square feet)

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  • Great information and suggestions Nora
    I switch my electricty off at the mains every night -I have a bunch of old fashioned lights with pull cords so switching off at the mains is much easier anyhow plus I don’t have to worry about overnight electrical faults starting a fire

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  • Thanks so much for the advice! It can be a real challenge
    cooling up a store when you can only control very little of the factors
    affecting the temperature! Thanks again!

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