How much does that extra MH heat cost you?

[zachfishman]

I'm trying to guestimate how much extra electricity a home A/C unit might consume because of one's MH fixture. More a point of curiosity than anything...

Say you have a 150w MH fixture, and say 1/2 of that (75w) goes straight to heat production... does it take my home A/C an equivalent amount of electricity to remove that heat? 1/2 of it? 1/4 of it? I know this will be an extreme generalization, but am I in the ballpark?

[Fish Keeper82]

Wow now there's a good question.
There would be a ton of variables that would change the outcome.
For instance if the thermostat is next to this heat source it would greatly effect the operation of your ac unit.If it was clear across the house it would be minimal to no influence.

Take an old 75 watt incandescent lamp. It is almost all heat and would be virtually the same as the 75 watt heat loss of the MH. No one really feels that heat it gives off standing under the light just a couple feet above your head. And more people were worried about the actual 75watts of the light staying on rather than any extra the ac would work.
I think here in texas you'd have a better calculation on how much temperature increase effects the ac every time you open an outside door and let cool air escape

[Fredfish]

Unless your airconditioner is 100% efficient, it would cost you more than one watt of power to remove one 'watt' of heat.

It's an intereting question though. I'm guessing you would need to convert watts of electicity in to some thermal unit and then look first at the efficiency of the air conditioner and then the power consumed per thermal unit of heat removed.

[d2mini]

I think this would really depend on the house, whether you have a canopy, etc.
I don't notice any additional heat in my house due to my tank lighting. Not saying its not there, but its not noticeable to me. I don't feel any warmth near the tank, unless I open the canopy and stick my hand in. I have an open floor plan, tall ceilings, an energy efficient house and hvac system... the main source of heat is the dang Texas sun.

[Greybeard]

When I last had a reef, it was a progressive thing... Add something, upgrade something, increase lighting, on and on. Ended up with several hundred gallons of water, several pumps, lots of lighting (MH and other). Never really saw the electrical cost... UNTIL... When I shut the tank down, my electric bill suddenly dropped nearly $100 per month, and that was a decade back, when energy was much cheaper.

Staying small this time, LED lighting... try and keep it efficient.

[Fish Keeper82]

Yeah just way too many variables.... this belongs in an engineering forum and they would argue forever every time someone thought of a new variable. How old is the refrigerant? Which way is the air circulating? Proximity to thermostat? Where is house? Will the heat added in winter offset heat added in summer? Sunny day or cloudy day?And on and on and on

[Fish Keeper82]

Originally Posted by Greybeard

When I last had a reef, it was a progressive thing... Add something, upgrade something, increase lighting, on and on. Ended up with several hundred gallons of water, several pumps, lots of lighting (MH and other). Never really saw the electrical cost... UNTIL... When I shut the tank down, my electric bill suddenly dropped nearly $100 per month, and that was a decade back, when energy was much cheaper.

Staying small this time, LED lighting... try and keep it efficient.

This is true however this is total power consumption ie..... 150 watts per MH and all equipment( several amps) VS just the heat loss of 1 MH(75 watts) zachfishman is referring to.

[zachfishman]

Originally Posted by Fredfish

Unless your airconditioner is 100% efficient, it would cost you more than one watt of power to remove one 'watt' of heat.

It's an intereting question though. I'm guessing you would need to convert watts of electicity in to some thermal unit and then look first at the efficiency of the air conditioner and then the power consumed per thermal unit of heat removed.

I tried investigating this, but getting into BTUs of AC units was dizzying. I suppose a "watt-for-watt" removal is a decent place to start (until someone jumps in with better info). That just means those LEDs pay for themselves faster Of course you can't add those cost savings in winter (heck if you're in a northern climate your MH lighting is reducing your winter heating bill).

[ca1ore]

It's hard to say. In a part of the country where it's cooler, MH lights mean you don't have to run the heaters as much - and may actually save you on your home heating.

[zachfishman]

Originally Posted by d2mini

I think this would really depend on the house, whether you have a canopy, etc.
I don't notice any additional heat in my house due to my tank lighting.

My house isn't any warmer either, but that's because my AC is keeping it at my set temperature. The extra heat contributed by the MH has to make my AC run slightly longer/more often in the summer months. Emphasis on slightly.

Originally Posted by d2mini

the main source of heat is the dang Texas sun.

Undeniably! These are small potatoes in the grand scheme.

[james30ct]

Cant you run mh for 5-6hrs vs running leds for 8-12?