Best 1000w HPS Bulb Test Comparison Review

What nine 1000w HPS lamps measured

Comparing lamps is only meaningful when nothing else moves. One reflector, one ballast, one mounting height, one grid, one sensor — the lamp is the only variable, and every reading is taken the same way.

How the readings were taken

The reflector hangs 24 inches above the measurement plane. Each lamp gets 20 minutes after striking to reach operating temperature and stable output, because an HPS arc tube read at two minutes and read at twenty minutes are two different lamps. A quantum sensor then takes seven readings: one at the centre of the footprint, and three along each of two axes at 6, 12 and 18 inches out.

The reflector is the OG Vertical Reflector, a pebbled-aluminium vertical hood. That finish matters to the result, and it shows up in the data as asymmetry — the two axes rarely agree exactly at the same distance, because a pebbled surface scatters rather than reflecting cleanly. Ballast choice matters too, and we measured that separately in the 1000w digital ballast comparison.

All 63 readings

Every figure below is micromoles per square metre per second, measured in the 400 to 700 nanometre band. Axis 1 and axis 2 are the two directions out from centre.

What the shape of the falloff tells you

Plot the two-axis mean at each distance and every lamp traces the same curve: steep through the first six inches, steeper still after twelve. Eighteen inches from centre, every lamp in the test has dropped to between 24% and 34% of its own centre reading. That is the number that decides how many fixtures a room needs, and it is invisible in any single-point measurement.

Manufacturers acknowledge up to 5% variance between individual lamps off the same line. Five of the nine here sit inside a 1.2% band in the centre, which is well under that tolerance — those five are not meaningfully different lamps on this measure, and treating a 3 µmol gap between them as a result would be reading noise.

Centre brightness is not the ranking

Rank the nine lamps by centre reading and you get one sequence. Rank them by the mean of all seven points — which is closer to what a canopy actually receives — and four lamps move, one of them by five places.

Why Digilux drops from third to eighth

Digilux posts the third-highest centre reading in the field at 1750. It also posts the lowest edge retention of any lamp here: 435 µmol at 18 inches, which is 24.9% of its own centre figure. Nothing is wrong with the lamp. It simply concentrates more of its output into a tighter cone, and a tighter cone reads brilliantly under the sensor and covers less canopy.

That trade is worth taking in a vertical rack or a single-plant footprint where the canopy sits directly below the hood. It is the wrong trade in a four-by-four where the corners are the plants you lose first.

Growlite and Maxlume move the other way

Growlite finishes eighth of nine on centre intensity and third on the footprint mean. Maxlume goes seventh to fourth. Both hold roughly a third of their centre reading at 18 inches, against Digilux's quarter. Across a full table, that spread does more for total canopy light than the 109 µmol that separates them from Digilux in the centre.

Where the dual arc lands

The Ultrasun Dual Arc finishes last on both measures, and the construction explains it. A 1000w dual arc lamp carries a 600 watt HPS arc tube and a 400 watt metal halide arc tube inside one jacket, firing together on a standard 1000w HPS ballast. Only 600 of those watts are doing the thing HPS does most efficiently. The lamp gains spectral breadth and pays for it in photon count — 1363 against 1960 for the leader, a 44% gap.

Its falloff is unremarkable at 32.6%, so the deficit is not beam shape. It is simply producing fewer photons in the band plants use. The format is still listed — the Real Red Double Arc in the HPS table further down is the current 1000w version — and for a one-fixture room that cannot swap lamps mid-cycle, that breadth can be worth the photons it costs.

PAR, lumens, and the unit that matters

A 1000w HPS lamp will be advertised at 140,000 or 145,000 lumens. That figure is real, it is measured correctly, and it was never meant to tell you anything about a plant.

What a lumen measures, and who it was measured for

Lumens weight light by human visual sensitivity, which peaks in the green at around 555 nanometres. High pressure sodium was developed as a street lamp, and the lumen figure on the box is a street lamp's figure — it describes how bright the lamp looks to a person standing under it. Sodium's output sits heavily in the yellow-orange, close to where the eye is most sensitive, which is exactly why HPS posts such flattering lumen numbers.

Plants weight light differently. Photosynthesis responds to photon count across 400 to 700 nanometres, and a red photon and a green photon are worth roughly the same to a leaf regardless of how bright they look. Measuring a grow lamp in lumens overstates sodium and understates anything blue-heavy, which is why a quantum sensor and not a lux meter is the instrument in this test.

µmol/s and µmol/J

Two numbers do the work. Photosynthetic photon flux is the total photon output in the 400 to 700 band, in micromoles per second, and it describes the lamp. Photon efficacy divides that by the watts going in, giving micromoles per joule, and it describes how economically the lamp produces them. A published 1000w single-ended HPS puts out 1750 µmol/s. A 1000w double-ended HPS on an electronic ballast runs about 1.7 µmol/J.

The readings in this test are a third quantity: photon flux density, measured at a point on the plane rather than summed over the whole sphere. That is the number a 1000w HPS PPFD chart shows, and it is the one that depends on your reflector, your hanging height and where in the footprint you stand the sensor. A lamp's PPF is a property of the lamp. PPFD is a property of your room.

What 1000w HPS lumens are actually worth

1000w HPS lumens are still useful for one comparison: the same lamp type at the same wattage. A horticultural 1000w HPS publishes around 140,000 to 145,000 lumens at 2000K. A general-purpose utility 1000w HPS of the same wattage publishes closer to 117,900 at 2100K, with a colour rendering index of 21 against 25. Same socket, same ballast code, noticeably less light — and the gap shows up in PAR too. If a lamp is sold without a sodium-spectrum horticultural specification behind it, the lumen figure is the first warning.

The HID lighting guide covers how metal halide and sodium spectra differ across a full cycle.

Single-ended against double-ended

Every lamp in this test is single-ended: a mogul E39 base at one end, an arc tube suspended inside an outer envelope, universal burning position. The double-ended format changes the geometry, and it changes the photon count.

The photon gap

A single-ended 1000w HPS publishes 1750 µmol/s — that is the Real Red mogul-base family in the HPS table further down, which runs the same lamp at 400, 600 and 1000 watts. The double-ended 1000w HPS lamps currently listed publish 2050 to 2100 µmol/s. That is up to 20% more photosynthetic photons from the same 1000 watts, which over a flowering cycle is the difference between adding a fixture and not needing to.

The mechanism is construction. A double-ended arc tube is supported at both ends rather than cantilevered from one, so it can be made smaller and positioned more precisely relative to the reflector. There is no frame or support wire inside the envelope casting a shadow. The lamp runs horizontally in a sealed fixture with ceramic end caps.

What the format costs you

Double-ended lamps are not a drop-in upgrade, and this is where growers get caught. A DE lamp needs a DE fixture — the socket geometry is different and there is no adapter. The lamps are sensitive to handling, since skin oil on quartz will cause early failure, so they go in with gloves or a cloth. Most DE fixtures are sealed with a glass pane, which the format depends on and which adds a surface to clean.

Single-ended keeps the advantages that come with being ordinary: the lamp drops into any mogul socket, works in an open hood, runs in any burning position, and can be swapped without tools. The full DE field is measured in the 1000w double-ended lamp test, and the Double Ended DE collection holds the fixtures that take them.

What replaces a 1000w HPS

"1000w HPS equivalent" is the most abused phrase in grow lighting, and the only honest way to settle it is photon efficacy — micromoles per joule, measured at the wall.

Efficacy, side by side

A 1000w double-ended HPS on an electronic ballast measures about 1.7 µmol/J. A 400w single-ended HPS on a magnetic ballast measures about 0.9 µmol/J, which is most of the reason nobody builds rooms on 400w magnetic any more. In independent testing, high-output LED fixtures have ranged from 1.13 to 2.59 µmol/J — a range wide enough that some LEDs test below a good HPS and the best test roughly 50% above a 1000w DE HPS.

In independent testing the two most efficacious LED fixtures measured approximately 50 percent more efficacious than the 1000-watt double-ended HPS fixtures tested.Runkle, Greenhouse Product News

What the claim is actually claiming

When a fixture is sold as a 1000w HPS LED equivalent, check which of three things is being matched. Photon flux means it emits a comparable µmol/s — the only version of the claim that holds up. Coverage means it lights a similar footprint, which depends entirely on optics and mounting height. Wattage means nothing at all, because wattage is the input, not the output.

A 1000w DE HPS at 2100 µmol/s is the number to beat. A fixture drawing 650 watts at 2.5 µmol/J emits about 1625 µmol/s — less total light, from less power, at better efficacy. Whether that is an upgrade depends on whether the room was photon-limited or power-limited, and those are different problems.

Heat is the other half. HPS puts a large share of its input into radiant and convected heat, which is a cost in summer and a free heater in winter. Rooms that switch to LED frequently discover their winter night temperatures were being held up by the lamps. The 300 to 400 watt alternative lighting test measures LED, ceramic and HPS against each other at a smaller scale.

Choosing a lamp for your fixture

The fixture decides more than the brand does. Socket type, ballast type and burning position rule out most of the field before spectrum enters the conversation.

Mogul base single-ended

An E39 mogul socket in an open or air-cooled hood takes a single-ended lamp in any burning position. Check the ballast before anything else: some horticultural single-ended lamps are specified for digital ballasts only and should not be run on magnetic. The Ballasts collection lists what drives them, and the Reflectors collection the hoods they sit in.

Metal halide for the vegetative half

Sodium is a bloom spectrum. Metal halide carries the blue end, keeps internodes tight and is what most growers run through veg before switching the same fixture to HPS. Double-ended metal halide is measured in the 1000w double-ended MH comparison.

Ceramic for a single lamp that runs start to finish

Ceramic metal halide trades peak intensity for spectral completeness and colour rendering above 90, which suits a one-lamp room that never swaps spectrum. Ten ceramic lamps are listed from 150 to 630 watts; the 315w field is measured head to head in the 315W CMH lamp comparison, and a ceramic sodium hybrid in the Hortilux SE ceramic HPS 600w review.

Fluorescent and work lamps

Three lamps in the range answer the jobs an HID fixture is wrong for: propagation shelves, clone domes, and seeing what you are doing during lights-out without resetting a photoperiod.

The full HID range, sodium and halide and ceramic together, sits in Bulbs (MH + HPS + CMH), and the sodium lamps alone in HPS Bulbs.

FAQs

The questions that come in by phone about 1000 watt sodium lamps, answered with the numbers from this test where the numbers apply.

Which 1000w HPS bulb measured brightest?

Eye Hortilux, at 1960 µmol/m²/s in the centre of the footprint and 1244 averaged across all seven points. It leads the next lamp by 8.7% in the centre and by 6.4% on the footprint mean, and it is the only lamp that finishes first on both measures. That makes it the best HPS bulb of the nine on raw output, by a margin wide enough to survive the manufacturing tolerance.

How much does the brand actually change?

Between the brightest and the dimmest lamp in this test, 44%. Between the brightest and second brightest, 8.7%. Between the five lamps in the middle of the field, 1.2% — which is inside the manufacturing tolerance manufacturers themselves quote, so those five are effectively the same lamp on this measure.

What are 1000w HPS lumens worth as a comparison?

It is accurate and it is the wrong unit. Lumens weight output by human eye sensitivity, peaking in the green; sodium's yellow-orange output sits near that peak, so HPS posts high lumen figures that overstate what reaches a leaf. Use µmol/s for the lamp and µmol/J for the running cost. Within one lamp type at one wattage, lumens still separate a horticultural lamp from a utility one — roughly 140,000 against 117,900.

Is a 1000w double-ended lamp worth changing fixtures for?

On photon count, yes: 2050 to 2100 µmol/s against 1750 for single-ended, up to 20% more from the same wattage. On practicality it depends on what you already own, because DE needs a DE fixture, gloved handling and a sealed glass pane. If the single-ended fixtures are in good condition and the room is not photon-limited, the money usually does more elsewhere.

What LED is equivalent to a 1000w HPS?

Match photon flux, not watts. The honest LED equivalent to a 1000w HPS is the fixture that emits the same number of photons: a 1000w DE HPS puts out around 2100 µmol/s, so an LED fixture is genuinely equivalent when it emits about the same. Measured LED efficacy spans 1.13 to 2.59 µmol/J, so the wattage needed varies by more than a factor of two depending on the fixture. Any claim stated purely in watts is telling you about the input, which is the part you pay for rather than the part the plant uses.

How far above the canopy should a 1000w HPS hang?

This test was run with the reflector at 24 inches, and at that height every lamp held between 24% and 34% of its centre intensity 18 inches out from centre. Raising the lamp flattens that curve and lowers the peak; dropping it does the reverse and raises leaf surface temperature. The reflector changes the answer as much as the height does, which is why a measured PPFD map of your own room beats any published figure.

Does a dual arc lamp replace running MH then HPS?

It replaces the lamp change, at a cost in photons. A 1000w dual arc runs a 600w sodium arc tube and a 400w halide arc tube together on one HPS ballast, and measured 1363 µmol/m²/s here against 1960 for the leading sodium lamp. For a single-fixture room where swapping lamps mid-cycle is not practical, that trade can be the right one. For a room with the fixtures to run a dedicated veg and bloom spectrum, it is not.

The bottom line

Nine lamps, one variable, 63 readings. Three findings survive the arithmetic.

Eye Hortilux is the best 1000w HPS bulb in this field, and it leads on both measures. 1960 µmol/m²/s in the centre, 1244 across the footprint, first on each. When a lamp leads on peak intensity and on coverage at the same time, there is no trade to weigh.

The middle of the field is one lamp with five names. Baddass, Solistek, Lumatek, Maxlume and Growlite finish inside 1.2% of each other in the centre — closer than the variance manufacturers quote between two samples of the same lamp. Choosing between them on a centre reading is choosing on noise. Their footprint averages separate them slightly more, and on that measure Growlite and Maxlume come out ahead.

A single number cannot rank a lamp. Digilux is third on centre intensity and eighth of nine across the footprint. Growlite is eighth in the centre and third across the footprint. Both facts come from the same seven readings. Which one matters depends on what sits under the hood: a single plant, or a full table.

The practical reading, for a room already running mogul-base fixtures: the best 1000 watt HPS grow light is the one at the top of the field, because the spread worth paying for sits there and not in the middle. For a room being built now, the 20% photon advantage of the double-ended format is a larger lever than any lamp-to-lamp difference measured here — and it is a fixture decision, not a lamp decision.

If you want help matching a lamp to the ballast and hood you already own, call us or send over what is in the room. That conversation takes ten minutes and saves a lamp that will not fire.