LED Lighting Retrofit Savings

Equal operating hours are assumed.

This selection changes review context only. Formulas and example inputs stay unchanged. Check the model assumptions and applicability for the actual process.

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1 Inputs

Minimum: 1

Minimum: 0

Minimum: 0

Minimum: 0

Minimum: 0

Minimum: 0

Minimum: 0

2 Results

Annual lighting savings
$2,880
Energy saved / year
24,000 kWh
Simple payback
0.9 yr
CO₂ avoided / year
9.6 t
10-year savings
$26,300
ΔE = N × (W₁−W₂) × h/1000
Equal operating hours are assumed. Energy savings alone fund simple payback; maintenance and rebates are excluded. Check equivalent illuminance, glare, colour requirements and installed cost before choosing replacement fixtures.

Worked example

Example values are illustrative. Replace them with your measured data.

InputValue
Number of fixtures100 count
Existing wattage / fixture100 W
New LED wattage / fixture40 W
Operating hours / year4000 h
Electricity rate0.12 $/kWh
Installed cost / LED fixture25 $
Grid emission factor0.4 kg/kWh

Annual lighting savings: $2,880

Related tools

About this calculator

How it works

You enter fixture count, existing and new watts per fixture, operating hours, electricity rate, installed cost per fixture and grid emission factor. kWh = fixtures × watts × hours ÷ 1,000 for old and new. Saving = difference × rate; payback = total install cost ÷ annual saving.

Worked example (illustrative inputs)

100 fixtures, 100 W to 40 W, 4,000 h: 40,000 − 16,000 = 24,000 kWh saved, $2,880 at $0.12. Install 100 × $25 = $2,500; payback ≈ 0.9 years; 9.6 t CO₂ avoided.

How to read the result

The tool marks payback of 2 years or less as good, up to 4 as fair and above 4 as poor. It also shows ten-year savings net of the install cost. Lamp-replacement labour savings are not included.

When to use it

Use it to rank lighting areas by payback; high-hour areas come first.

À propos de ce calculateur

Traduction (brouillon) — à relire.

Fonctionnement

Vous saisissez le nombre de luminaires, les watts actuels et nouveaux par luminaire, les heures, le tarif, le coût installé par luminaire et le facteur d'émission. kWh = luminaires × watts × heures ÷ 1 000, avant et après. Économie = différence × tarif ; retour = coût d'installation total ÷ économie annuelle.

Exemple chiffré (valeurs d'illustration)

100 luminaires, de 100 W à 40 W, 4 000 h : 40 000 − 16 000 = 24 000 kWh économisés, 2 880 $ à 0,12 $. Installation 100 × 25 $ = 2 500 $ ; retour ≈ 0,9 an ; 9,6 t de CO₂ évitées.

Lire le résultat

L'outil juge un retour de 2 ans ou moins bon, jusqu'à 4 ans correct et au-delà faible. Il affiche aussi l'économie sur dix ans nette du coût d'installation. Les économies de main-d'œuvre de remplacement des lampes ne sont pas incluses.

Quand l'utiliser

Utilisez-le pour classer les zones d'éclairage par temps de retour ; les zones à forte durée d'allumage passent en premier.

حول هذه الحاسبة

ترجمة (مسودة) — للمراجعة.

طريقة الحساب

تُدخل عدد وحدات الإنارة والواط الحالي والجديد لكل وحدة وساعات التشغيل والتعرفة وتكلفة التركيب لكل وحدة ومعامل الانبعاث. kWh = الوحدات × الواط × الساعات ÷ 1000، قبل وبعد. التوفير = الفرق × التعرفة؛ والاسترداد = تكلفة التركيب الكلية ÷ التوفير السنوي.

مثال محسوب (قيم توضيحية)

100 وحدة، من 100 W إلى 40 W، و4000 ساعة: ‏40,000 − 16,000 = 24,000 kWh موفّرة، أي 2880 $ عند 0.12 $. التركيب 100 × 25 $ = 2500 $؛ والاسترداد ≈ 0.9 سنة؛ و9.6 طن من CO₂ متجنَّبة.

قراءة النتيجة

تعدّ الأداة استردادًا خلال سنتين أو أقل جيدًا، وحتى 4 سنوات مقبولًا، وما فوقها ضعيفًا. وتعرض أيضًا توفير عشر سنوات بعد خصم تكلفة التركيب. ولا يشمل الحساب توفير عمالة تبديل المصابيح.

متى تستخدمه

استخدمها لترتيب مناطق الإنارة حسب مدة الاسترداد؛ المناطق ذات ساعات التشغيل الطويلة أولًا.

In one line

Equal operating hours are assumed. Energy savings alone fund simple payback; maintenance and rebates are excluded. Check equivalent illuminance, glare, colour requirements and installed cost before choosing replacement fixtures.

Worked example

EXAMPLE

Illustrative values (the calculator defaults), not data from a real site.

Inputs
Number of fixtures100 count
Existing wattage / fixture100 W
New LED wattage / fixture40 W
Operating hours / year4000 h
Electricity rate0.12 $/kWh
Installed cost / LED fixture25 $
Grid emission factor0.4 kg/kWh
Results
Annual lighting savings$2,880
Energy saved / year24,000 kWh
Simple payback0.9 yr
CO₂ avoided / year9.6 t
10-year savings$26,300

Frequently asked questions

How much energy do LED retrofits typically save?

LEDs typically use 50 to 70% less energy than the fixtures they replace, so most of the savings in this calculator comes directly from the wattage difference you enter multiplied by your operating hours — high-hour spaces like warehouses or 24/7 plants see the largest dollar impact because the savings accrue every hour the lights are on.

What counts as a good payback period for a lighting retrofit?

LED retrofits are often one of the fastest-paying-back energy projects in a facility, commonly landing in the 1 to 3 year range for high-hour spaces, and utility rebates (not modeled in this tool) can shorten that further. Longer paybacks generally point to low operating hours or a small wattage difference between old and new fixtures.

Does this calculator include maintenance and relamping savings?

No, it only models energy cost, install cost and CO2 — it does not add the labor savings from LEDs' much longer rated life, often around 10 times longer than the fixtures they replace, which lowers relamping and maintenance labor separately from the energy savings shown here.

Should I add occupancy sensors or daylight dimming to the retrofit?

Yes, where the space isn't continuously occupied — these controls stack on top of the lamp-wattage savings this tool calculates and often pay back quickly on their own in intermittently used areas, though you'd need to model their cost and savings separately from this basic fixture-swap calculation.

What if I don't know the exact installed cost per fixture?

Get a quote from a lighting contractor or supplier for your specific fixture type and site conditions — installed cost varies with fixture type, mounting height and whether existing wiring or ballasts need modification. A rough estimate is fine for an early screening calculation like this one, but confirm before committing budget.

How is CO2 avoided calculated?

It multiplies the kWh saved per year by your entered grid emission factor (kg CO2 per kWh), which should reflect your local electricity grid's fuel mix — this factor varies significantly by region, so use your utility's or national energy agency's published figure rather than a generic default for an accurate carbon estimate.

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