One Heater. The Real Decision Is How You Switch It.

Only the control. Both are the same two stage 34,000 BTU heater, running 25,000 BTU on low and 34,000 on high. The TSR is wireless: a handheld remote and a wireless wall control ship with it, and it powers from an included 7.5 VDC adapter into an ordinary outlet, so there is no control wiring to run. The TSH is hardwired to a lighted Hi/Lo switch on the wall, part 12052, on a 24 VAC circuit, with no remote to lose and no batteries to replace. AEI points commercial installations at the TSH for that reason.

AEI publishes an approximate 10 by 10 foot footprint for the 25,000 BTU S25 and an approximate 12 by 12 foot footprint for the 34,000 BTU models, and labels both approximate. In a cold or windy climate AEI revises those down to roughly 10 by 10 feet for an S34 and 8 by 8 feet for an S25. Where more than one heater is needed, the spec sheet gives 10 feet as the average spacing between them. Sunpak publishes no square footage rating and no BTU per square foot rule, so treat any such figure you see elsewhere as somebody else's arithmetic.

There is no published minimum, only a typical range and a warning to check your local code. The installation manual states that some local codes require every part of an overhead radiant heater to sit at least 8 feet above the floor. AEI's spec tables give 7 feet 6 inches to 9 feet 6 inches as typical for the S25, and 8 to 9 feet horizontal or 7 to 8 feet at a 30 degree tilt for the S34, TSR and TSH. AEI's own FAQ separately suggests 9 feet 6 inches to 12 feet for the S34, which does not agree with its tables, so we use the tables and let the clearance figures and your local code set the real limit.

It depends on the model and the angle, and Sunpak publishes one table for each. Mounted horizontally, the S25 needs 12 inches behind, 9 inches above, 24 inches at the gas inlet end and 48 inches clear below the mounting. The S34, TSR and TSH share a second set: 17 inches behind, 13 inches above, 24 inches at the inlet end and 48 inches below. Tilted to the 30 degree maximum, the rear clearance on both drops to 8 inches while the ceiling clearance rises, to 14 inches on the S25 and 18 inches on the 34,000 BTU models. These are minimums to combustible material, set at a surface temperature 90 degrees Fahrenheit above room temperature, and AEI notes that glass, painted surfaces and vinyl siding may need more room still. The casing finish makes no difference: Sunpak publishes the same table for stainless steel and black.

Yes, as long as the clearances above are maintained, and it must not be recessed into the ceiling or a soffit. What it cannot do is sit in a fully enclosed space. Sunpak's own definition of outdoors is walls on all sides with no overhead cover, or an overhead cover with no more than two side walls, or an overhead cover and three walls as long as 30 percent of the horizontal periphery is permanently open. The heater is unvented, so it also needs 4 cfm of supply and exhaust air per 1,000 BTU of input.

No. AEI answers this directly: Sunpak heaters are approved for outdoor residential use, and the manual says the heater is not approved for any indoor residential application, an attached garage included. AEI also rules out ice fishing tents, barns, boats, RVs, and any enclosed living space for people or animals.

A gas line, a low voltage control circuit and a contractor. On the gas side Sunpak requires a minimum half inch inlet pipe, a drip leg or sediment trap in the supply to each heater, and a half inch lever handled shutoff valve within 6 feet of the appliance, with a minimum inlet pressure of 6 inches W.C. on natural gas or 11 inches W.C. on propane. On the electrical side the S25, S34 and TSH need a 24 VAC Class 2 transformer rated at least 20 VA per heater, and a 40 VA transformer will run two; the TSR uses its own included 7.5 VDC adapter instead. Mounting supports have to carry a working load of at least 75 pounds. AEI is blunt about who should do it: this is not a project for the weekend do it yourself person, and they recommend a licensed, bonded HVAC contractor.

Up to 30 degrees, and the one exception is worth knowing before you order. Sunpak allows a mounting angle of 0 to 30 degrees or face down, and requires the heater to stay level lengthwise and never be mounted vertically. The S25 on propane is specified for the horizontal position only, so if you want the heat aimed at the seating on propane, the S34 is the one that tilts.

It changes how much you feel, and there are two published numbers for two different questions. The certified wind rating on the spec sheet is 10 mph horizontal. Separately, AEI says a continual breeze of 20 mph or more will make heating any patio difficult. The manual also warns that severe updrafts, the kind you get on a raised terrace or a rooftop patio, can damage the heater. Sunpak's own advice is to place heaters where the heat loss is greatest, such as the open side of a semi protected patio.

Sunpak states 5 to 10 degrees Fahrenheit outdoors, and both AEI and the installation manual give the same figure. Because this is infrared, it warms people and surfaces rather than the air, which is why it works at all in an open space where heated air would simply drift away.