TSL-800 vs 1000W HPS: Power, Heat and Payback of a 1:1 LED Swap

If you run 1000 W HPS in flower and want to switch to LED without re-engineering the room, the question is not "is LED better" but "what does a 1:1 swap cost and when does it pay back." This post works the numbers for the TSL-800, an 800 W fixture built to hang exactly where a 1000 W HPS was.

What "1:1 replacement" means

The TSL-800 covers a 5 × 5 ft flowering footprint from the same mounting points as a 1000 W HPS hood, on the same 208–277 V circuits, so you keep your rack spacing, your light schedule and your controller wiring. What changes:

	1000 W HPS (double-ended, typical)	TSL-800
Power at the wall	about 1,050 W with ballast	800 W
Light output (PPF)	roughly 1,700–2,100 µmol/s, depending on lamp and ballast	2,400 µmol/s
Efficacy	about 1.7–2.0 µmol/J	3.0 µmol/J
Spectrum	HPS yellow-orange	GC-3KF Bloom Phase, CRI 86+
Cooling	air-cooled hood or open DE	passive, no fans
Mounting height	36 in and up (heat)	6–24 in
Lamp replacement	lamp is a consumable	none; L90 rated life > 54,000 h
Dimming	ballast-dependent	0–10 V, 10–100%
Warranty	varies	5 years

HPS figures are typical published values for a 1000 W double-ended lamp and ballast; check your own lamp's spec sheet, because output drops as the lamp ages.

Electricity: what one fixture saves

Every TSL-800 draws about 250 W less than the HPS it replaces. On a 12-hour flowering day:

• 250 W × 12 h = 3.0 kWh saved per fixture per day

• 3.0 kWh × 365 = about 1,095 kWh per fixture per year

What that is worth depends on your rate:

Electricity rate	Savings per fixture per year	Savings per 100 fixtures per year
$0.15 / kWh	$164	$16,400
$0.20 / kWh	$219	$21,900
$0.30 / kWh	$329	$32,900

Use your blended commercial rate, including demand charges, not the advertised per-kWh number. In California the blended rate for a cultivation facility is often well above $0.20.

Heat: the second saving

Watts you don't put into the room are watts you don't have to pull back out. 250 W less per fixture is about 850 BTU/h less heat (1 W = 3.41 BTU/h). Across 100 fixtures that is 85,000 BTU/h, roughly 7 tons of cooling you no longer need to run during lights-on. We don't put a dollar figure on this because it depends on your HVAC efficiency and climate, but for most rooms it is the second-largest line in the payback.

Payback on electricity alone

At $1,099 per TSL-800:

Electricity rate	Payback from electricity only
$0.15 / kWh	about 6.7 years
$0.20 / kWh	about 5.0 years
$0.30 / kWh	about 3.3 years

Three things shorten that in practice:

1. No lamp changes. HPS lamps lose output and get replaced on a schedule; the TSL-800 has no lamp to replace.

2. HVAC. The 850 BTU/h per fixture above.

3. Utility rebates. The TSL-800 is DLC listed, which is the usual prerequisite for horticultural lighting rebates. Ask your utility what it pays per fixture or per watt reduced before you order; the rebate can cover a meaningful share of the fixture price.

Counted together, payback typically lands well inside the 5-year warranty.

What stays the same, what to check

• Circuits: the TSL-800 runs on 208–480 V. It does not run on 120 V. At 240 V it draws 3.4 A; at 277 V, 2.9 A.

• Hanging points: same as your HPS. Fixture weight is 32 lb.

• Height: you can bring the TSL-800 down to 6–24 in above the canopy. If you leave it at HPS height you give away intensity, so plan to lower it and dim to taste.

• Control: 0–10 V. The Master Controller runs up to 100 TSL-800s per group with sunrise/sunset ramps, or use the 0–10 V controller you already have.

• Spectrum change: plants under HPS are used to a red-heavy, low-blue spectrum. Expect tighter internodes and a short adjustment period under the 3KF bloom spectrum; we suggest starting at 70–80% and ramping up over the first week.

FAQ

Can I replace just some of my HPS fixtures and run both? Yes. Mixed rooms are common during a phased changeover. Keep the LED and HPS zones on separate dimming groups.

Does it need a separate driver or ballast? No. The driver is built in; you plug the fixture into the circuit.

What about 480 V rooms? A 480 V version is available for commercial projects; email info@growerschoice.ag.

Is the 5 × 5 ft coverage at full power? Yes, in flower. For veg it covers 6 × 6 ft.

Shipping and returns? Shipping is free within the contiguous U.S. Unused fixtures in original packaging can be returned within 14 days with an approved RMA; a 25% restocking fee applies and the customer pays return shipping.

Want the payback worked for your room? Email info@growerschoice.ag with your fixture count, electricity rate and lights-on hours and we'll send back the numbers.