What Do Efficiency Ratings Mean, Anyway?

Whether you’re comparing wood, gas, or pellet-fuel appliances, you’ll see an efficiency rating listed in the product information. Between uncertain fuel costs and increasingly strict air quality regulations, more and more consumers are looking for the most efficient heaters they can find. But what do those ratings mean? How are they measured?

The bad news is that there isn’t one standard rating system used by manufacturers, nor are they required to tell you which system they’re using. The good news is that by learning a bit about what the ratings mean, you can put manufacturer claims in context and compare apples to apples when buying a stove or fireplace.

What does “efficiency” actually mean?

In the simplest terms, the efficiency rating on an appliance tells you how much of your fuel will become usable heat in your home. A pound of wood, gas, or pellets contains a certain amount of potential energy; some of this energy will be used in starting and sustaining combustion, some of it will go up the chimney (carrying away particulates and other undesirable byproducts of combustion), and the rest will come out into your home as heat.

Wood Heat: EPA vs. Real-World Performance

Wood stoves and inserts are sometimes advertised with two efficiency ratings: EPA and cordwood/real world performance. EPA testing procedures are focused mostly on particulate emissions, and are very highly standardized. These tests use milled lumber (often pine), precisely stacked, with the stove draft set to its lowest (and smokiest) setting; this is also referred to as a “crib wood” test. While this is useful for determining how much air pollution a stove will generate, it has very little to do with how efficiently your stove will convert firewood into usable heat in your home. Many companies choose to do their own testing with cord wood (usually hardwood) and realistic venting setups, in order to give their customers a more accurate idea of stove performance. Unfortunately, there’s no requirement that companies tell you which efficiency rating they’re listing. For environmental impact, focus on the emissions listing (gm/hr of particulates released into the atmosphere) rather than the listed efficiency rating. For real-world efficiency, a good rule of thumb is that 67%-75% is a good range for quality non-catalytic stoves, with catalytic stoves occupying the 75%-83% range.

(Note: just to make this even more confusing, the EPA is currently in the process of revising its compliance and listing standards. While this process is ongoing, look for “cordwood/HHV/actual measured efficiency (CSA)” in your stove literature.)

Gas Heat: Steady-State vs. AFUE/EnerGuide

Gas stoves, inserts, and fireplaces are rated in two different ways. The Steady State efficiency rating, which offers a higher and more impressive number, is taken only once, after the appliance is fully heated up and burning steadily. While this number is technically accurate, it has very little to do with how your stove will perform over the course of its lifetime, and under real-world conditions. We prefer to work with vendors who list the EnerGuide, P4, or AFUE (annual fuel usage estimate) ratings. These efficiency readings reflect performance over the entire burn cycle, from ignition to cool-down, and use realistic venting setups. If you’re looking at efficiency ratings, and seeing numbers in the high 80% range, you’re probably looking at the steady-state efficiency of the fireplace. The more honest EnerGuide, P4, and AFUE rating systems give numbers ranging from around 60%-70%. A 65% efficiency rating is actually quite good, and an 85% rating, although it sounds much better, probably doesn’t reflect an actual increase in real-world efficiency or performance.

To sum up: efficiency ratings can be confusing, and don’t always give a complete picture of how an appliance will perform in your home. However, with a little bit of time and research, you can put those numbers in context when comparing different products, and make a more informed decision about which stove, fireplace, or fireplace insert will be the best fit for you!

 

Spring Inventory Reduction Clearance Sale!! Up to 80% Off!

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Big changes are afoot here at the Wooden Sun! Over the summer, we have plans to remodel our store, bring in new product lines, and expand our work into more outdoor projects! To make room for new products and displays, we’re putting all of our showroom units on sale, at discounts ranging from 10%-80% off our usual retail pricing. From April 15th-May 22nd, come into the Wooden Sun showroom for big discounts on a wide range of gas & wood stoves, fireplaces, fireplace inserts, and outdoor cookers! And be sure to look for our grilling accessories, on clearance from 10%-25% off retail price!

At the same time as we bid a fond farewell to our old inventory, we’d like to welcome the Kamado Joe line of ceramic grills and smokers to the Wooden Sun family! Every Kamado Joe cooker comes standard with cooking racks, rolling cart, grill lifter, and ash tool, so you can get started grilling right away. These grills will also be included in our sale, at 10% off retail.

No Power? No Problem!

Early 2015 brought us a lot of winter storms, and winter storms always bring at least one big power outage. Out in the country, it can be days before you get your power back, but you’ve got to stay warm in the meantime. Fortunately, Wooden Sun has your winter heating needs covered.

Valor G3Valor gas fireplaces and inserts are designed to function without a fan, and therefore without the need for electricity. In addition to the convection heating you get from all gas fireplaces and inserts, Valor has some of the best radiant heat technology in the industry. While few Valor appliances are large enough to heat your entire home, they will easily keep a few rooms warm and cozy while you wait for the power company to do its thing.

Regency Hampton H300Wooden Sun carries a variety of wood-burning stoves and inserts, to heat anywhere from 600-3000 square feet. While inserts often work best with blowers, they’ll still put out quite a bit of heat without the fan, so you don’t lose your heating capability when the power goes out (your faithful blogger has a wood insert with a very noisy blower, and she can get a great deal of heat out of the appliance without having to resort to the fan).

WiseWay pellet stoveWe’re also very excited about our most recent addition, the Wise Way brand of gravity-fed pellet stoves. While other pellet stoves rely on electric motors and augers to get the pellets from the hopper to the burn chamber, Wise Way pellet stoves have a simple gravity-feed system, which means you can still use your stove when the power goes out. Note: the zig-zag portion of the stove is actually the outlet from the burn chamber, which means that you can see the fire through the window on the side as it streaks upwards!

 

 

Common Gas Fireplace Problems: You Probably Don’t Need to Panic

Following up on our recent post about how to address concerns about wood stove performance, here’s a post about your gas stove/insert/fireplace. Since the direct vent gas appliance is a closed system, drawing air from and venting to the outside, there’s much less variation from home to home and appliance to appliance. However, there are a few issues that can crop up with gas units, so here are some common service requests we get, with a couple of troubleshooting steps to try on your own:

My Fireplace Won’t Turn On

At the beginning of each fall, we get a lot of service requests from people trying to turn their gas fireplaces on for the first time in several months, only to find that those fireplaces won’t start. The first, and most obvious question: how are the batteries? Your gas appliance may have batteries in both the remote and the receiver, so it’s important to read your owner’s manual to figure out how many sets of batteries you need to check. It seems obvious, but we’ve gone out to fix several malfunctioning gas appliances, only to discover that the only thing the customer needs is new batteries. It’s worthwhile to keep a battery tester around the house to help you determine whether or not that pack of AAs in the kitchen drawer is still good.

If the batteries in your remote and/or receiver are good, the next step is to make sure the fireplace is getting fuel. If you have a propane tank or natural gas line, are the tank and valves set in the on position? Your gas appliance should have a valve in the firebox, or a key in the wall or floor nearby, and the propane tank will have a knob on the tank outside that opens or closes it. For problems with a natural gas line, contact your city utilities office, and for propane, contact your propane company.

And if you can get your fireplace going, but it keeps turning itself off suddenly, check to see if you’ve left it set in thermostatic mode. We often have that problem in the showroom over the summer, particularly with units we don’t turn on very often; we’ll set the remote to act as a thermostat over the winter, and then in the summer, the fireplace keeps automatically turning itself off!

The Glass on My Fireplace Looks Smudged

Each time you start your gas fireplace, you’ll notice some condensation on the glass. This is a normal part of the startup process, as the water vapor in the air inside the firebox begins to evaporate. This condensation will dissipate within a few minutes, as the firebox heats up and the flames turn yellow. Over time, you can get some buildup on the inside of the glass (residue from that startup condensation), but this is harmless, and easily cleaned off during your annual maintenance call.

My Fireplace Smells Weird

When you start your gas fireplace for the first time after it’s installed, there will be an “off-gassing” period as the residual factory paints finish curing. This, again, is harmless; open the window for your first couple of fires, and the gasses should dissipate fairly quickly. When you then start your fireplace, stove, or insert for the first time each year, you’ll get a slight odor for that first fire or two, as small amounts of dust that have built up over the summer burn off. This shouldn’t last very long; if it lasts more than a couple of hours, or if you start to smell gas or plastic, shut your fireplace off and call your local certified gas appliance expert.