For a given set temperature, the operating cost will be the same for either voltage. The higher wattage will reach the set temperature faster ( quicker temperature rise). Fans in such heaters tend to be noisy.

so the higher voltage cost more but gets there sooner...sounds like it might be the way to go...any experience with these...I understand you remove a section of drywall and in the fg sulation and they sit between the studs, the back up against the xps I have against the concrete...I assume the back does not get hot enough to be a fire hazard!...?

I put in a 240v version of one of these. Worked quite nicely, the metal box around it did not get significantly warm (being paranoid I checked before enclosing it with wallboard.) Be sure you get a UL listed version--and double check it!

Was is very loud? Did you get the model with the digital programmable thermostat or the regular knob model?

Just the knob. Something that could have been programmed to turn off automatically would have saved me checking all the time whether the kids left it running.

Loud is pretty subjective-- you could definitely hear it running, but it didn't interfere with watching the TV we had down there. Louder than the regular hot air furnace, not as loud as a cheesy bathroom fan-- probably on a par with a medium-good quality bathroom fan.

he said highest wattage, not highest voltage.

say again?

delete

This post was edited by bus_driver on Wed, Sep 10, 14 at 7:17

bus: "The higher wattage will reach the set temperature faster ..."
you: "so the higher voltage cost more but gets there sooner..."

yes, so wouldn't I want this is the question? Upon reading reviews, one review noted:

Oh there is also a nice feature to make the heater only use 110 which i haven't tried but will try soon and see if it keeps it as warm.

....would this not cause the unit to run longer to heat the same space thus costing more in the long run?

I posted earlier: "For a given set temperature, the operating cost will be the same for either voltage. The higher wattage will reach the set temperature faster ( quicker temperature rise). Fans in such heaters tend to be noisy."
Watts and volts are not the same thing but they have a definite mathematical and electrical relationship.
Either the questioner did not read my post carefully or did not grasp the meaning. For basic understanding of Volts, amperes and watts, Google is your friend.
Buy the book!

Here is a link that might be useful: Book

Under most circumstances you'd _expect_ the higher voltage app. to be higher wattage. As with a clothes drier, most of which are 30A/240V for a potential usage over 5000W. Unless the OP mistyped and meant "4000W" for the 240V device, it isn't the case here. A 400W 240V fan is using (and providing!) less energy/heat than a 1500W one. In spite of the higher voltage.
A good time to remember click & clack's little saying of "twinkle twinkle little star, power equals I squared R"

It is not necessary to understand volts and wattage in order to read the nameplate and apply what I posted earlier. 400W is watts!! 1500W is watts!! Which of those is larger?

" The higher wattage will reach the set temperature faster
( quicker temperature rise)."

And what part of this is difficult to understand?
"For a given set temperature, the operating cost will be the same for either voltage."

Maybe an analogy would make the situation clearer.

Imagine you are filling two identical buckets with water. One you are using a garden hose, the other you are using a firehose.

The firehose will fill the bucket really quickly.
The garden hose will take longer, but it will still get there.

In both situations, you've used the same amount of water.

The firehose is analogous to the higher wattage heater.
The bucket is the room you are heating.
The water is the electricity used.

Really good analogy.
With rooms, the heat energy is always in the process of escaping, assuming that the surroundings of the exterior are at a lower temperature. So the heat source must be sufficient to both raise the temperature and compensate for the loss of energy. There are reliable means of calculating the probable loss for any enclosed area. But that is beyond the scope of this forum.
The bucket is somewhat leaky. The fire hose will fill it faster and is more likely to keep it filled.

Installation costs may be a little cheaper for a 240v vs 120v.

If the two heaters are identical wattages, then the 240v heater may be installed with a thinner wire.

Higher voltage, same wattage, means lower amperage. Wire sizes are based on amperage.

good lord..sorry I stirred this up. I DID HAVE A TYPO....one heater is 120V and 1500W and he other is 240V and 4000W! (four thousand)

Without getting into the math, I think you all are saying......without buying the book :)......

that both should end up costing the same...the lager v/w would do it quicker....

The wiring issue is mainly current, not volts, although they are related. Power is volts times amps, so for the 120 volt heater, it will draw 1500/120 which is 12 1/2 amps, which would probably require a 20 amp dedicated circuit (its own 20 amp breaker with 12 gauge wire). If you went with the much higher power 4000 watt heater, then you would need 4000/240 = 16 2/3 amps. I'm not sure if the electrical code allows that to be run on a 20 amp circuit, but it would require a dedicated 240 volt line, which will take up two positions on your breaker box. Cost for an electrician to run these would probably be the same (labor is the same), but material cost somewhat higher for the 240 volt version.

To me, 4000 watts seems to be awfully high for a basement rec room, but it will heat it faster.

Thanks! The unit says it warms 400 sq ft which is about what I have....the temp likely will not drop below 63 down there so I am hoping it could somewhat quickly warm it up to 68 or so. without jacking up my electrical bill more than a 1500W unit would..again...assumption being it will warm the area quicker and shut off faster than the 1500W unit.

The breaker situation is not an issue..we had a separate box installed for the basement. Whatever is safestshould be installed.

The 4000w unit will heat up faster but at the same time use more power per unit time interval. It might just be a 'wash' as to your power bill but the joy of having fast heat would make me favor this.

I think my parents had a similar heater (convective/radiant, ie no fan) in the room furthest from the furnace. It could crank out a lot of heat.