Philips Alto F48T8/TL835/HO 44W T8 High Output Fluorescent Lamp – 3500K Natural White | 4000 Lumens | CRI 86 | R17d Base | 800 Series

The Philips Alto F48T8/TL835/HO is a 44-watt high-output T8 fluorescent lamp producing 4,000 initial lumens at 3500K with CRI 86 — delivering elevated lumen output and premium color rendering in the same 48-inch T8 high-output form factor. Trichromatic phosphors, Philips lowest-level mercury Alto technology, and >95 lumens per watt efficacy make this the correct specification for commercial, retail, and healthcare T8HO fixtures where natural white color quality and maximum output are both required. R17d recessed double-contact base — confirm T8HO fixture and ballast compatibility before ordering.

Quick Specs

• Brand: Philips
• Series: Alto 800 Series
• Lamp Code: F48T8/TL835/HO/ALTO
• Lamp Type: T8 High Output Linear Fluorescent
• Wattage: 44W
• Color Temperature: 3500K (Natural White — TL835)
• CRI: 86
• Initial Lumens: 4,000 lm
• Mean Lumens: 3,600 lm
• Lamp Efficacy: >95 lumens per watt
• Rated Average Life: 18,000 hours
• Base: R17d Recessed Double Contact
• Overall Length (MOL): 48 inches
• Diameter: 1 inch (T8)
• Phosphor Technology: Trichromatic (800 Series)
• Mercury Technology: Philips Alto — Lowest-Level Mercury

Product Overview

The Philips Alto F48T8/TL835/HO is a 44-watt high-output T8 fluorescent lamp from the Philips 800 Series — producing 4,000 initial lumens at 3500K natural white with CRI 86. This is the 3500K variant of the Philips T8HO Alto platform, specified for commercial environments where the natural white color temperature is preferred over the cooler 4100K TL841 while maintaining the same high-output performance level.

At 3500K, this lamp delivers a balanced, mid-range color quality — warmer than cool white (4100K) but crisper than warm white (3000K) — making it the preferred specification for offices, retail environments, hospitality spaces, and healthcare facilities where a comfortable, neutral light quality is as important as light output. CRI 86 renders colors accurately under 3500K natural white, supporting both merchandise presentation and occupant visual comfort.

Philips 800 Series trichromatic phosphors deliver improved lumen maintenance compared to halophosphate lamps — mean lumens of 3,600 at the midpoint of the 18,000-hour rated life indicate that light levels are well-maintained over time. Alto technology uses the industry’s lowest mercury content at manufacturing, reducing environmental impact before end-of-life disposal. Lamp efficacy exceeds 95 lumens per watt.

Why Choose This Product

• 4,000 initial lumens at 3500K: Full T8HO light output in natural white — higher output than standard 32W T8 lamps in the same 48-inch fixture position, with the balanced color quality of 3500K rather than the clinical coolness of 4100K.
• CRI 86 — 800 Series color quality: Premium trichromatic phosphor color rendering above standard 700-series CRI 78 lamps — accurate color representation in retail, hospitality, office, and healthcare environments.
• 3500K natural white: The preferred mid-range color temperature for mixed-use commercial environments — appropriate where 4100K feels too cool and 3000K feels too warm.
• >95 lumens per watt efficacy: Industry-leading efficacy for the 44W T8HO category — maximum light output with controlled energy consumption.
• Philips Alto lowest-level mercury technology: Mercury minimized at the manufacturing stage — supports environmental compliance and reduces disposal risk across the lamp’s 18,000-hour service life.
• Trichromatic phosphors with improved lumen maintenance: Light levels decline more slowly compared to halophosphate lamps — consistent illumination throughout the full rated life.
• 18,000-hour rated life: 50% longer than standard 12,000-hour fluorescent lamps — reduces maintenance frequency and total lamp replacement cost.
• Direct retrofit for existing T8HO fixtures: R17d base and 48-inch length are the standard T8HO configuration — drop-in replacement in properly rated T8HO housings.

Technical Specifications

Dimensions

Applications

The Philips Alto F48T8/TL835/HO 3500K T8HO is specified for T8 high-output fixture applications where natural white color temperature and premium color rendering are required alongside elevated light output:

• Commercial offices and open-plan workspaces – 3500K natural white in T8HO fixtures provides high light levels with a comfortable, balanced color quality — avoiding the clinical coolness of 4100K in high-output environments.
• Retail environments – CRI 86 and natural white output enhance merchandise color accuracy across apparel, home goods, and general retail without the blue-shift of cool white sources.
• Hospitality and hotel environments – Balanced 3500K natural white suits front-of-house lobby, corridor, and function space T8HO fixtures where light quality matters as much as output level.
• Healthcare facilities – CRI 86 supports accurate color rendering in patient areas and clinical support spaces at 3500K — warmer than 4100K while maintaining color accuracy for clinical use.
• Educational facilities – High-output 3500K natural white in classroom and gymnasium T8HO fixtures supports both visual comfort and footcandle targets.
• T8HO lamp replacement and upgrade programs – Direct replacement for existing Philips TL835/HO and compatible R17d T8HO lamps; Alto low-mercury technology improves environmental compliance versus older T8HO formulations.

Replacing Your Current T8 High Output Lamp?

This is a T8 High Output lamp — not a standard T8. Confirm the following before ordering:

• Base type — R17d recessed double contact: This lamp uses an R17d recessed double-contact base, not the G13 medium bi-pin used on standard 32W T8 lamps. Confirm your fixture uses R17d lampholders. Installing this lamp in a G13 bi-pin socket is not possible without lampholder replacement.
• Ballast type — T8HO ballast required: This 44W high-output lamp requires a ballast specifically rated for T8HO operation. Standard T8 ballasts rated for 32W will not correctly drive this lamp. Verify your existing ballast is rated for T8HO before ordering.
• Wattage: 44W — verify your ballast and fixture are rated for 44W T8HO operation.
• Color temperature: This lamp is 3500K natural white (TL835). If replacing TL841 (4100K cool white) T8HO lamps, note the warmer color shift. If replacing TL830 (3000K warm white) lamps, note the slightly cooler shift.
• Also available in 4100K: If your installation specifies cool white (4100K), the equivalent lamp is the Philips Alto F48T8/TL841/HO/ALTO — same wattage, base, and output at 4100K.
• Fixture length: 48-inch MOL — the standard T8HO length. Verify your fixture housing accepts 48-inch lamps.

Ordering Information

• Brand: Philips
• Lamp Code: F48T8/TL835/HO/ALTO
• Series: Alto 800 Series
• Lamp Type: T8 High Output, 44W
• Color Temperature: 3500K Natural White (TL835)
• Base: R17d Recessed Double Contact
• Case quantities and bulk pricing: Contact ADL Supply for volume orders.

Compliance and Certifications

• Philips Alto Low-Mercury Technology: Yes — lowest-level mercury content at manufacturing
• Verify RoHS compliance status with manufacturer specification sheet.
• Verify TCLP compliance with manufacturer specification sheet.
• Verify California Title 20 / T24 compliance with manufacturer specification sheet.
• Verify Prop 65 warning requirements with manufacturer specification sheet.

ADL Supply recommends confirming all applicable compliance data with the Philips official product data sheet prior to specification or installation.